Any Apps/data that you synchronise via iCloud will be kept in-step across all devices. For example, deletion of notes on one device will be mirrored across all you devices; similarly, addition or changes to a note will also synchronise.
To break this link, you simply need to disable iCloud synchronisation for the particular App or service that you do not wish to synchronise with iCloud or between devices.
From device settings:
Settings > [Your Name / AppleID] > iCloud > [Apps Using iCloud] Show All - enable or disable individual Apps and services as required
The iPad User Guide is a rich source of information about iPad. Here is a link to the relevant pages of the Guide that explains iCloud and how to use its many services:
Use iCloud on iPad - Apple Support
The full User 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