Use Crop, Rotate, and Geometry tool in Lightroom

Select the Crop, Rotate, Geometry icon. 

To resize your photos,

• Drag the Crop overlay handles to adjust the Crop.
• Select the desired aspect ratio in the Aspect menu. Using the Rotate Aspect Ratio button, rotate the Crop overlay 90 degrees and unlock the Constrain Aspect Ratio button to adjust the aspect ratio freely.
  

Use the Straighten slider to adjust the overall image alignment. Using the drop-down menu, select a Crop Overlay to choose from helpful compositional guides.

Use the Upright menu to select automatic or manual Guided Upright perspective corrections.

Select the Auto Upright icon to automatically correct a photo's perspective. Choose the Guided Upright button to make perspective corrections manually by drawing guides directly on the photo.

Use the Transform slider to adjust the following:

• Distortion slider helps in adjusting the distortions often caused while capturing the photo
• Vertical slider helps in adjusting the vertical perspective, like straightening up or titling a vertical line  
• Horizontal slider helps in adjusting the horizontal lines
• Rotate slider helps in rotating the image in a clockwise or anticlockwise direction 
• Aspect slider helps define the aspect ratio of the entire image 
• Scale helps in zooming in or out of the image without affecting the aspect ratio
• X Offset helps in moving the image right or left 
• Y Offset helps in moving the image up or down

Check the Constrain Crop checkbox to restrict the Crop Overlay to the visible image area.