How to shorten a Recorded video

Navigate to the video in question in the photos app. If the user interface isn’t visible, only black bars / fullscreen video, tap again on the video, and the user interface should appear. Click edit, and use the white toggles (with arrows), to select a part of the video you want. You can use the play button to preview the part of the video that will be there after the edit. Hit done, and wait for the video to render (there’s a progress pie chart displayed on screen). Send the video using the share menu. If it’s still too long, repeatedly shorten the video, and render it until it’s compressed enough.

Alternatively, click Copy iCloud Link in the share menu, to send a link that’s available for 30 days (and gives the receiver the option to download the video permanently), to send the full video. Just paste the link into your Messenger chat. Hope this helps.