How to Enter Recovery Mode on iPad, iPad Air, iPad Mini, Early iPad Pro
Sometimes an iPad must be placed into Recovery Mode before it can be restored or updated successfully with a computer. For example, if an iPad gets stuck on a black screen with an Apple logo for a very long time, Recovery Mode can usually remedy that. Typically Recovery Mode is used for a troubleshooting endeavor, but it can also be used for downgrading from iOS beta / iPadOS beta versions as well.
The instructions here will show how to enter Recovery Mode on iPad, iPad Air, iPad mini, and the earlier iPad Pro models with a Home button. Basically if the iPad has a Home button, the instructions detailed here will work to put the iPad into Recovery Mode. However, any newer model iPad Pro without any front buttons and with Face ID instead must use these instructions to enter Recovery Mode instead on iPad Pro 2018 and newer devices.