Thank you.
But how would one edit the header code to put something custom in using code snippet plugin? I would like to add a search bar, there is no hook or anything in the place I want it. So I need to modify header.php.
Or can code snippet plugin override the theme header.php file with my own header.php file so then its OK for it to be updated?
Also, child themes should not be updated, they are there so one can make edits to override the parent. Your theme should not be updated or it should be a parent theme. Or you supply a second child theme based on this, which is not updated, if you want to continue to update the first. And make it clear it will be updated, as many people will expect a child theme not to be.