Apple does publish Manuals for each major release of its Operating Systems - and whilst they are obviously device-generic, they do clearly highlight feature differences between device models.
Simply go to the Apple Bookstore App on your device - and search for Apple to see all the downloadable manuals. If you search specifically for iPad User Guide for iPadOS, you’ll find the latest version of the document. User Guides are also available for Apple’s major Productivity Apps - such as Numbers, Pages and Keynote - and other devices.
These [free] downloadable resources are often overlooked. There is also an online version for the most current version of the OS, although, in my personal opinion, the downloadable version is superior in many ways. Here is a link to the online version:
https://support.apple.com/en-gb/guide/ipad/welcome/ipados
I hope you find this helpful in resolving your question.