Most social media platforms allow you to share videos from your camera roll. To do this on an iPhone, first select the video you want to share. Then tap the Share button in the lower left corner of the screen. A menu will appear with several options for sharing the video. Tap the icon for the platform you want to share it on. For example, to share a video on Instagram, tap the Instagram icon. The app will open and you can complete the process of sharing your video.
When you record a video on your iPhone, it's automatically saved to your phone's camera roll. From there, you can share it on any social media platform that allows you to post videos from your camera roll.
To do this, first select the video you want to share. Then tap the Share button in the lower left corner of the screen. A menu will appear with several options for sharing the video. Tap the icon for whichever platform you want to use (Instagram, Facebook, etc.). The app will open and you can complete whatever process is necessary for posting your video on that particular platform.