How can I make existing custom fields easier to edit/add in my theme?

A WordPress theme I have authored uses Custom Fields on posts.

There are about 5 or 6 custom fields to set when authoring a post, and my users have a hard time remembering what to enter for the name and value of the custom field. I’ve been using the name/value fields for many years so a lot of content is built up based on them.

I’m looking for a way to make the post creation / editing process easier for my users.

Is there built in functionality in WordPress that I could use that would make existing custom fields not be a field where they have to manually enter the name, but instead a dropdown or select of the custom field that appears on the post being edited? Is this what meta boxes are for? Or is it better to use a plugin?

(I’m starting to get familiar with the Carbon Fields plugin for a different project, but I can see it’s creating its own namespace for custom fields and I am not sure how I would use the plugin given I have existing fields on my site).

In general the answer is yes and the web is full of good tutorials that would do a better job than I can here.