basic questions on tags for M4A files

I'm considering switching to apple hardware for music playback, in which case I'd need to convert all my FLAC files to M4A, but I don't have the hardware yet to test tag results so I have a few basic questions:

When I look at extended tag info on the few M4A files I have, up at the top of the popup box it says "Tags - MP4 (MP4)". That makes sense to me. But when I look at the setup options for Mp3tag, under Tags>MPEG, I don't see any selection that relates to the type of tag in the M4A files I have for either reading or wrting.

Since I know that the files I have are tagged correctly for what I want to do, what selection(s) do I need to make on the MPEG options page to get MP4 tag format written correctly to my potential new M4A files?

I also use Mp3tag to edit ID3v2.3 tags in my MP3 files, so do I need to unselect ID3v2.3 in the writing area of the MPEG options page when I edit M4A files?

Or do I need to do nothing to change my existing write settings that I picked for MP3 files - will Mp3tag automatically do something appropriate for writing when it sees files with a M4A extension? If Mp3tag will do something automatically regarding write behavior based on seeing a M4A extension, what will it do?

Thanks for any insight.

You don't have to change any settings.
There's only one tag format that Mp3tag uses for m4a so there are no tag options for m4a files.