New to MP3Tag and need advise

i have just started using mp3tag and curious about a couple of things
1 can it edit M4B format or audiobook
2 Can the interface be made bigger or even just the writing
3 the interface on the left,can the fields be edited so you can choose what fields to edit
thanks in advance

For supported formats, see: https://www.mp3tag.de/en/index.html#formats

For ways to adapt the GUI, see the help: http://help.mp3tag.de/options_tagpanel.html

MP3tag uses the system font settings. You would have to modify those to get changes in the size of labels etc.