Can I delete everything in my document folder in my imac and macbook?

The document folder doesn't contain any system files for the OS but might contain files that certain apps need to run properly. For example, if you edit video and photos some of your footage might be stored in the Documents folder and if you go back to edit the video your project files might be gone and can't be recovered.

yeah. it won't let you delete important system files.

Nsnn

You should be able to delete what is in that folder without any problem. However if you are worried try deleting a few at a time and leave them in your recycle bin where they can be restored if needed.

Ron