How to save Instagram videos to your camera roll?

You cannot save Instagram videos to camera roll in your phone. There is no feature to download it direct to your phone. You can only save it to your Instagram app.

Open the app, choose the video you want to save. Tap on the save button right corner in the line of like, comment and share. Your video will be saved in your profile. You can see it in the profile tab in the save button icon in the right corner.