Missing columns from selling > sales sections. How can i get back?
Assuming that you have refreshed the browser and it is like this I would guess this is permission issue. In your case, open the role permission manager, open doctype “Quotation” and make sure you have at least read access to it, then open the menu again and it will show up.
Case 2 could be if you have modified the selling.py file in ERPNext, in which case there is most probably a syntax error. Best revert back using git.