On iPhone:
1. Go into your Settings app.
2. Choose Wallpaper.
3. Select Choose a New Wallpaper.
4. To choose a live photo, tap Live in the options at the top of the screen and then choose a live photo.
On Android:
You'll need a third-party app to set up a live wallpaper on an Android. Here's how to do it using the Video to Wallpaper app:
1. Open the Video to Wallpaper app.
2. Tap the plus + sign, located in the bottom-right corner of the screen.
3. Tap Choose and then select your desired video and tap Ok.
4. Select Apply and then Ok to continue.
5. Choose Video to Wallpaper from the list and then Set Wallpaper.
6. Choose to apply the live wallpaper to just your homescreen or your homescreen and lock screen.