Open the Photos app
Select the video you want to edit
Tap Edit
Trim the video by dragging the start and end sliders
Tap the filter icon to apply a filter
Tap the adjustment icon to change brightness, contrast, exposure, and more
Tap the crop/rotate icon to crop, straighten, or rotate the video
Tap the mute icon to remove or restore sound
Tap Done to save the changes
Choose Save Video or Save Video as New Clip if prompted
Open iMovie for more advanced editing
Tap Create Project
Select Movie
Add your video clips
Trim, split, and rearrange clips
Add text, music, transitions, and effects
Tap Done and share or save the final video