The Apple Beta Software Program allows anyone to run next generation software on their Apple devices. iOS 15 and its new features are in the works, and Apple has delivered the latest beta to participants in the program. As usual, there could be bugs or other problems with versions of iOS that are not yet fully baked.
Should you wish to remove iOS 15 from your iPhone, iPad, or iPod touch immediately, it's possible to downgrade. After downgrading from iOS 15 beta back to iOS 14, the final release of iOS 15 can be installed after it's officially launched this fall.