are there manuals I can download for iPad Pro 12 6th generation in PDF format?

Apple hasn’t published User Guides in PDF format for some time; those that are available will be for much older versions of iPad and iOS - and will be significantly out of date.

The iPad User Guide is a rich source of frequently overlooked information about your iPad and iPadOS. The Guide is available both online using a web browser (such as Safari), or as an Apple Books download:

iPad User Guide - Apple Support

https://books.apple.com/book/id1567104892

The Tips App, installed by default on all new models of iPad, provides a brief introduction - and leads you to the User Guide. In case you missed it, here is a link to the Tips App:

https://apps.apple.com/gb/app/tips/id1069509450

Apple also has a huge YouTube Channel - containing videos and feature guidance:

https://www.youtube.com/user/Apple

There are also comprehensive guides for Apple’s main productivity Apps, such as Numbers (spreadsheets), Pages (documents) and Keynote (presentations):

Numbers User Guide for iPad - Apple Support

Pages User Guide for iPad - Apple Support

Keynote User Guide for iPad - Apple Support

Hereyou go:

Apple - Support - Manuals

what you really want is a user guide for the iOS version you are running. That defines the behavior of the device.

This free Apple iBook may have more details:

https://books.apple.com/us/book/ipad-user-guide/id6443147167

Your iPad came with the Books app installed so will allow you easy access to the manual.