Before you distribute a PDF, you may want to examine the document for sensitive content or private information that can trace the document to you. Use the Redact tools to remove or redact sensitive images and text that are visible in a PDF.
Use the Remove Hidden Information feature to find and remove hidden content from a PDF. For example, if you created the PDF, the document metadata normally lists your name as the author. You may also want to remove content that can inadvertently change and modify the document’s appearance. JavaScript, actions, and form fields are types of content that are subject to change.
Redaction is the process of permanently removing visible text and graphics from a document. You use the Redact tools to remove content. In place of the removed items, you can have redaction marks that appear as colored boxes, or you can leave the area blank. You can specify custom text or redaction codes to appear over the redaction marks.
If you want to locate and remove specific words, characters, or phrases, use the Find Text tool 
instead.
Open the PDF in Acrobat, and then do one of the following:
(Optional) To set the appearance of redaction marks, click the drop-down in the Redact toolset in the secondary toolbar, and choose Properties. (See Change the look of redaction markers.)
To preview how your redaction marks appear, hold the pointer over the marked area.
To apply multiple code entries to a single redaction, right-click a redaction mark and select an option. For more information, see Apply multiple code entries to a redaction.
(Optional) To repeat a redaction mark, right-click it and choose Repeat Mark Across Pages. This feature is convenient if a particular header, footer, or watermark appears in the same location on many pages.
When you have finished marking the items you want to redact, click Apply in the secondary toolbar to remove the items. Alternatively, you can Save the document, and then choose Apply & Save.
In the Apply Redactions dialog, choose if you want to Sanitize And Remove Hidden Information by clicking the toggle button, and then click OK.
The items aren’t permanently removed from the document until you save it.
The Save As dialog is displayed. Specify a filename and location. The suffix “_Redacted” is appended to the filename. If you don’t want to overwrite the original file, save the file with a different name, at a different location, or both.
Use the Find Text tool to find and remove words or phrases in one or more PDFs that contain searchable text.
The Find Text tool doesn’t search secured (encrypted) PDFs.
Open the PDF in Acrobat, and then do one of the following:
The Redact toolset is displayed in the secondary toolbar.
Click the drop-down and choose Find Text & Redact.
In the Search dialog box, specify if you want to search the current PDF or all PDFs in another location.
Click Search & Remove Text.
If you selected occurrences that you want to mark for redaction, click Mark Checked Results For Redaction.
The items you selected in the list are shown marked for redaction.
If you haven’t saved the file, you can select redaction marks in the document and press Delete to remove the redaction mark. The redaction marks become permanent after you save the file.
To remove the marked items, click Apply in the secondary toolbar.
In the Apply Redactions dialog, choose if you want to Sanitize And Remove Hidden Information by clicking the toggle button, and then click OK.
The items aren’t permanently removed from the document until you save it.
The Save As dialog is displayed. Specify a filename and location. The suffix “_Redacted” is appended to the filename. If you don’t want to overwrite the original file, save the file with a different name, at a different location, or both.
Use the Remove Hidden Information feature to find and remove content from a document that you don’t want, such as hidden text, metadata, comments, and attachments. When you remove items, additional items are automatically removed from the document. Items that are removed include digital signatures, document information added by third-party plug-ins and applications, and special features that enable Adobe Reader users to review, sign, and fill PDF documents.
To examine every PDF for hidden content before you close it or send it in email, specify that option in the Documents preferences using the Preferences dialog box.
Open the PDF in Acrobat, and then do one of the following:
The Redact toolset is displayed in the secondary toolbar.
Click Sanitize Document. In the Sanitize Document dialog, to remove hidden information, click Click Here.
If items are found, they are listed in the Remove Hidden Information panel with a selected check box beside each item.
Click Remove to delete selected items from the file, and click OK.
Choose File > Save, and specify a filename and location. If you don’t want to overwrite the original file, save the file with a different name, at a different location, or both.
The selected content is permanently removed when you save the file. If you close the file without saving it, repeat this process, making sure to save the file.
Metadata
Metadata includes information about the document and its contents, such as the author’s name, keywords, and copyright information. To view metadata, choose File > Properties.
File Attachments
Files of any format can be attached to the PDF as an attachment. To view attachments, choose View > Show/Hide > Navigation Panes > Attachments.
Bookmarks
Bookmarks are links with representational text that open specific pages in the PDF. To view bookmarks, choose View > Show/Hide > Navigation Panes > Bookmarks.
Comments And Markups
This item includes all comments that were added to the PDF using the comment and markup tool, including files attached as comments. To view comments, choose Tools > Comments.
Form Fields
This item includes Form Fields (including Signature fields), and all Actions and calculations associated with form fields. If you remove this item, all form fields are flattened and can no longer be filled out, edited, or signed.
Hidden Text
This item indicates text in the PDF that is either transparent, covered up by other content, or the same color as the background.
Hidden Layers
PDFs can contain multiple layers that can be shown or hidden. Removing hidden layers removes these layers from the PDF and flattens remaining layers into a single layer. To view layers, choose View > Show/Hide > Navigation Panes > Layers.
Embedded Search Index
An embedded search index speeds up searches in the PDF file. To determine if the PDF contains a search index, choose Tools > Index and then click Manage Embedded Index in the secondary toolbar. Removing indexes decreases file size but increases search time for the PDF.
Deleted Or Cropped Content
PDFs sometimes retain content that has been removed and no longer visible, such as cropped or deleted pages, or deleted images.
Links, Actions And JavaScripts
This item includes web links, actions added by the Actions wizard, and JavaScripts throughout the document.
Overlapping Objects
This item includes objects that overlap one another. The objects can be images (composed of pixels), vector graphics (composed of paths), gradients, or patterns.
Sanitize documents removes all sensitive information, hidden or not, from your document so that the information is not passed along when you publish your PDF.
It removes:
Open the PDF in Acrobat, and then do one of the following:
The Redact toolset is displayed in the secondary toolbar.
Click Sanitize Document. The Sanitize Document dialog box is displayed.
Click OK. Specify a filename and locaton. If you don't want to overwrite the original file, save the file with a different name, at a different location, or both.
Click Save to save the document and automatically finish the sanitization process.
The sensitive information is permanently removed when you save the file. If you close the file without saving it, repeat this process, making sure to save the file.
Choose Edit > Preferences (Windows) or Acrobat > Preferences (Mac OS).
From the Categories on the left, select Documents.
In the Redaction area, choose a language from the Choose Localization For Search & Remove Text Patterns menu. Then click OK.
By default, thin red outlines appear around images and text you mark for redaction, and black boxes appear in place of redacted images and text. You can set the default appearance of redaction marks before you mark items for redaction. You can also change the look of redaction marks before you apply the redactions.
Open the PDF in Acrobat, and then do one of the following:
The Redact toolset is displayed in the secondary toolbar.
Click the drop-down, and choose Properties. The Redaction Tool Properties dialog box is displayed.
On the Appearance tab, select options you want to change, and then click OK:
Custom Text
Displays text you type into the Custom Text option over the redaction mark.
Font
Displays custom text in the selected font.
Font Size
Displays custom text in the selected point size.
Auto-Size Text To Fit Redaction Region
Resizes custom text to fit within the redacted area. When selected, this option overrides the Font Size setting for the overlay text.
Font Color
Displays custom text in the selected color, which you can change by clicking the color swatch.
Repeat Overlay Text
Fills the redacted area with as many instances of the custom text as needed, without changing the font size. For example, if you specify the letter x or a hyphen (-) as the custom text, these characters are repeated throughout the redacted area.
Text Alignment
Aligns text to the left, right, or center.
Acrobat uses overlay text to overprint areas selected for redaction. One example of overlay text is a redaction code, which consists of one or more code entries from a code set. Acrobat includes the U.S. FOIA and U.S. Privacy Act code sets that you can use. You can use either codes or custom text to create overlay text. The difference is that redaction codes are text entries that you can save, export, and import. One code set can contain multiple codes.
Codes don’t save the current attributes for overlay text as part of the code definition, such as colors, font characteristics, and repetition or size of text. Codes only make the overlay text itself reusable in future sessions and by other users with whom you share code sets. You set other attributes for the code in the Redaction Tool Properties dialog box.
Open the PDF in Acrobat, and then do one of the following:
The Redact toolset is displayed in the secondary toolbar.
Click the drop-down, and choose Properties. The Redaction Tool Properties dialog box is displayed.
Select Use Overlay Text.
Select Redaction Code.
In the Redaction Code Editor dialog box, click Add Set.
(Optional) Type a new name for the set in the text field below the list of code sets, and then click Rename Set.
Click Add Code, and type the text that you want to appear as overlay text in the text field below the list of code entries, and then click Rename Code.
Open the PDF in Acrobat, and then do one of the following:
The Redact toolset is displayed in the secondary toolbar.
Click the drop-down, and choose Properties. The Redaction Tool Properties dialog box is displayed.
Select Use Overlay Text, and then select Redaction Code.
Select a code set from the list on the left, and click Edit Codes.
In the Redaction Code Editor dialog box, do any of the following:
With the Code Set selected, select the code entry that you want to edit, and do one of the following:
Right-click the redaction marker.
Select a Code Set from the list at the bottom of the context menu, and then select a code entry from the drop-down menu. A check mark appears next to the code entry when the code is applied.
Repeat the previous steps to add another code entry to the redaction.
Hold your pointer over the redaction mark to see the code entries, each one separated by a comma.
To apply the same code to multiple redactions, set the redaction properties before you mark the content. In the secondary toolbar, click Properties. Select Use Overlay Text, then select Redaction Code. Select a Code Set and a code entry, then click Add Selected Entry.
