You have probably already discovered that Instagram has launched the new feature "Reels". Reels is not yet available in all countries, but will be unlocked for more zones as time goes on. Currently there are reels in Brazil, Germany and France.
The new feature allows users to create creative videos within the Stories function. The clips are always limited to 15 seconds of playtime and allow users to use your music if you have enabled delivery to Facebook/Instagram for this.