Rotate a video or photo
You can rotate video clips and photos to change the orientation of a video. For example, you can rotate a video that you have captured on your phone in portrait orientation to convert it to landscape orientation or you can flip an upside-down video.
How to rotate a video clip or photo1 In the Timeline, click a video clip or photo.
2 In the Options panel, click the Edit tab, and click Rotate Left 
or Rotate Right 
until the orientation you want displays in the Preview panel.
or Rotate Right until the orientation you want displays in the Preview panel.