To update your iPad, go to Settings , tap on General, then tap on Software Update. Then, tap on Download and Install underneath iPadOS 15.1.
If your iPad is out-of-date by many iterations, you will instead see Upgrade to iPadOS 15 underneath the current update. Tap on Upgrade to iPadOS 15 instead of installing any other update. Afterwards, follow the previous steps to check for any other updates, such as 15.1, and install them.
Please allow your devices at least one hour to fully update. It may take several hours (depending on the speed of your internet connection) to download an update, followed by several more minutes to install.
If you encounter any issues while following these steps, please send a Help Desk ticket to your Site IT Administrator.