How to work with the site code, which is already planted on the CMS?

Question

CMS

For example, the situation - I put the site on MODX, uploaded it to a server, everything works.
There was a need to make changes in the code, let's say it's a bunch of small changes.
In this case, I'm supposed to make these changes to my local project, and then push it back to the CMS? Or that I will be making changes to a running project? In what way?
Editor - PHPStorm.
Thanks in advance, sorry if this is a stupid question.

Answer 1

put the site on MODX

grandfather planted a turnip
There is such a thing as version control. But if you use them, then what prevents you from creating a copy of what is on the server locally and making changes, and then uploading it via ftp? You probably have a local copy. The same phpStorm has built-in ftp and the ability to compare file versions.
Can you enter the code printed on the printer into the local or bring into the kitchen the code printed on the printer, that's just the point? Of course, if you want edits to change a working project, then you need to make them into a working project.
Right-click in phpStorm on a file or folder, then deployment and there upload or sync or compare (depending on the need). It is convenient to set up a hotkey for this.

Answer 2

Scheme of working with CMS, its settings:
Plugins, settings, themes - basically.
Rarely-rarely - your plugin or your fix for existing plugins or the core.
What you mean is a bad approach.
You can, of course, if there is no other way.

Answer 3

I would recommend this editor slusar.su/redaktiruem-sayt-po-ftp if you know FTP access. Or Atom + FTP plugin.