Accessing Notes

Thr Notes app can be deleted and then reinstalled like any other app from App store. I would do that if my next post does not help

Make sure Notes is turned on in your icloud Settings so they are safe.

Have you tried adding a new folder by tapping the link?

Have you tapped the pencil in square icon to create your first note?

This is what you should see

create folder F1

Then hit pencil