Is there an off-line user guide for iPad Pro (M4)?

You're very welcome.

Hopefully Apple will again see the value in releasing a downloadable version of its User Guides. By definition, online resources are only accessible if you have access to an internet connection; conversely, downloadable versions are useable regardless of having access to the internet...

You are not the first - and are perhaps unlikely to be the last - in seeking a readily accessible offline User Guide for iPad and iPadOS.

For reasons known only to Apple, a downloadable User Guide (previously made available via the Apple Books App) has not been released for iPadOS 17/18. User Guides are currently only available as "online" versions - accessed using a web browser or the Tips App.

Clearly, limiting access to offline reference material is distinctly unhelpful if you don't have immediate access to an internet connection - or if you have a problem that prevents you accessing online resources. It is perhaps worthwhile to note that similar User Guides for iPhone, AppleTV and Mac are similarly also now restricted to online access.

Apple does invite submission of comments and feature requests via its Product Feedback portal. If you would like Apple to reconsider their current approach - and reinstate availability of downloadable User Guides - you would be strongly advised to make an appropriate request via this communication channel. For iPad and iPadOS:

Feedback - iPad - Apple