With some models of iPhone and iPad, you can shoot Live Photos, which include both a still image and the moments just before and after the image. Not all apps can play Live Photos; in some cases you just see a still image. You can also use your iOS device (iOS 11 or later), iPadOS device, or Mac (macOS 10.12 or later) to add Loop, Bounce, and Long Exposure effects to Live Photos. In iCloud Photos, Live Photos with these effects appear with a badge and play in video format.
See the Apple Support article Take and edit Live Photos.