If you can't share or collaborate in the Notes app on your iPhone or iPad - Apple Support

To share or collaborate in the Notes app, everyone needs an Apple device with the latest operating system and enough storage. You can also use iCloud.com.

How to collaborate with others in Notes on iPhone, iPad, and iPod touch — Apple Support

Collaborate on projects with Messages on iPhone - Apple Support

How to Move Notes on iPhone & iPad from iCloud to Device, & Vice Versa

Why can't I collaborate on notes? - Apple Community

Share lists and collaborate in Reminders on iPhone - Apple Support

iCloud User Guide - Apple Support

Collaborate on projects with Messages on iPhone - Apple Support

iPad User Guide - Apple Support

Use Notes on your iPhone, iPad, and iPod touch - Apple Support

Apple Freeform Lets You Brainstorm and Collaborate on Mac, iPad, and iPhone - The Mac Security Blog

Can not open shared notes - Apple Community

Can't share or collaborate in Notes app on iPhone? 6 Ways to fix it! - iGeeksBlog

15+ New Apple Notes Features for iPhone and iPad That Will Finally Make It Your Go-To Notes App « iOS & iPhone :: Gadget Hacks

How to draw with friends in Notes on iPhone, iPad, and iPod touch — Apple Support

Note Sharing Not Working - Apple Community