iOS 15 was reveled at WWDC keynote 2021 and would be available publicly later this year with the upcoming iPhone 13 series devices.
Users can currently test the new update to iOS installing a developer beta but we do not recommend doing that. These developer betas are buggy and meant to be installed on secondary devices by developers to test their apps on the system that would come out later in the year.

Find out what’s new in iOS 15 here
Find out what’s new in iPadOS 15 here
How To Install the iOS 15/iPadOS 15
You need to register as an Apple developer if not already registered. You can register as a developer here.
- Create a backup of your supported iPhone and/or iPad on your PC or Mac in case you decide to downgrade back to a stable version. (Note the developer betas can be extremely buggy and we recommend having a backup before moving to next step.)
- After creating an backup open your web browser and head to Apple Developer Website.
- Go to the Downloads tab from the navbar.
- Swipe down and tap Install Profile next to your device type.
- Head to settings app on your device. Open Profile Downloaded near the top.
- Now tap Install and enter your passcode.
- Once you read the agreement and accept it tap install.
- Your iPhone/iPad will now require a restart.
- After the reboot head to Settings>General>Software Update.
- You can now see the new available as an OTA update. You can now update to the latest developer betas as they are available.