Can I add a file (rather than an image) to a note? How to manage such files later?
You surely can. Click on Attachments.
Press on Add file to add the file. You can add several files at a time. The file can then be renamed or deleted. To do that, right-click on the file and select the option you need.
I do not see the file I imported in the note (PDF or RAR for example). How do I find it?
Open the window with attachments.