Here at How-To Geek, we think iOS's live wallpaper feature is pretty neat, although it's underused. Live Wallpaper, one of the best options to use in GIF.
There's an app for that. In this case, it's GIPHY, one of the best GIF apps on iOS. Download it and get it started.
Open GIPHY and search for a GIF you like. There are a few things to bear in mind:
- Your iPhone wallpaper is vertical. GIF, you should look for something that's vertical.
- Live Wallpaper are stationary most of the time. You should pick something where the still frame looks good.
- GIFs generally have low image quality. It's worth spending a bit of time to find something that's high quality.
Once you've found your GIF, open it and tap the three little dots in the bottom right corner. Next, select "Convert to Live Photo."
You'll have two options: Save as Live Photo (Full Screen) and Save as Live Photo. 
Full Screen crops the GIF, so it takes the whole of your iPhone's display while Fit to Screen adds black bars. Select the one you want and the Live Photo wants to get saved to your Camera Roll.
Now, it's time to set your wallpaper. Go to Settings> Wallpaper> Choose New Wallpaper.
Select "Live Photos" and then the live photo you just saved. Position the GIF as you want it and then tap "Set." You can choose whether you want it on the Lock Screen, the Home Screen, or Both.
And with that done, you'll have a stupid, sexy new GIF as your background.
Setting your favorite GIF as your wallpaper is a great way to add some personality to the millions of other people using it. You can even make and set your own GIFs.