If you intend to turn Motion ON or OFF for ALL photos, please see the FAQ on "Photo Motion" in the Project Settings section. This FAQ pertains to editing individual photos and videos only.
On the Video tab, tap the tile of the photo or video you want to modify. Tap Edit Photo (or Edit Video). Now tap the Motion/Crop icon (last tab on the bottom right) to view the Motion/Crop settings.
To turn the Motion effect off:
Tap the Motion toggle to set it from ON (default) to OFF.
To adjust the Motion effect:
Swipe to switch between the starting frame and the ending frame. Crop or re-position each frame as you see fit. The effect will cause the photo or video to gradually transition from your selected starting point, to your selected ending point.
If you want to adjust the cropping and position of the photo or video:
use the pinch/zoom gesture to increase or decrease the zoom
long press and then drag to re-position the frame of reference