Where do code additions get saved?

I’m enjoying your page builder plug-in so far.

If I use your Shortcode Widget or your HTML Widget to add a shortcode to one or more pages, does that code addition get saved in the theme files or somewhere else?

I’m asking because I’m told that if code gets inserted into theme files, then a child-theme first is the safe way to build.

Sorry if this is a dumb question as I am new to WordPress and I am not a designer nor do I have coding skills.

Thanks.