Uploading a Live Photo is pretty similar to uploading your standard still — in fact, it’s identical, save for one extra step. While uploading a photo from your camera roll that happens to be Live Photo-enabled, a “LIVE” box appears in the bottom right; tap that, and it’ll upload as a Live Photo. Don’t tap it, and only the still goes up.
In your feed, Facebook shows static photos by default but if you see the Live Photos icon at the bottom right of a photo you can tap and hold the photo to start playing.
Any device that runs iOS 9 will be able to view Live Photos in Facebook but only the iPhone 6s and iPhone 6s Plus are able to capture them.
In addition to Facebook, Tumblr also gained support for Live Photos earlier this month.
You can download Facebook from the App Store for free.