I have added custom fields and sections to DocTypes (Quotation, Invoice, Sales Order), directly, without using the Customize Form. But new knowledge recommends making changes /additions via the Customize Form not directly, as this may cause conflicts when updating ERPNext.
SInce my site is already operational, how can I “move” these changes to Customize Form and leave the original doctype definitions?
From my experience, you better use the customization, not touch “mandatory” fields (they’re often very functional), and create a new app and export your customization as fixtures.
Since you’re using docker, you can spin up a new one and duplicate your changes bit cleaner
You should log into the server and give it a git status to see what files you’ve modded. You can stash and pop them, or save 'em into an archive and duplicate the changes on a different instance of ERPNext.