So I try to add new, or any manipulation. But the most important question. How to save edits? ESRI tell me to click save. But where's "save" button?
So I found save button in the ribbon menu
But save command is currently disabled due to my improper (I assume) changes. Description tells:
Save is enabled when there are valid edits to the fields, but disabled if the current project contains unsaved feature edits.
I tried many edits but all came to disabled save button.
So I have finally solved all my troubles. You can't save fields while editing. Just save editing and after that you can change fields options!