Where is the action file stored in mac version? "mta" files location.
Also, in Extended tags menu
The button should be "OK" instead of "EDIT". We are already in edit mode. In mac, most GUI's use "OK" to accept the changes. Please check the same in iTunes, which is the closest app to mp3tag.
The Mac version differs in that regard from the Windows version and stores all its preferences in the global user defaults system of macOS. See also FAQ → Can I import data from Windows?
Thanks also for the pointer regarding button titles. From the Human Interface Guidelines:
Use verbs in push button titles. An action-specific title shows that the button is interactive and conveys what happens when clicked. For example, Save, Close, Print, Delete, and Change Password are action-specific titles.
According to this, I think it's not wrong to use Edit in that context — especially because the field is edited after pressing the button.
I was asking myself the same question "why edit?"
I vote for "save" ("speichern" in German).
"OK" is appropriate. The inner popup window do not save the tag.
"SAVE" button is in the main dialog box.
hmm, I still vote for "save".
I think it is a question of context. We enter this dialog box by double click a tag field. Then we edit this field in the focus of this dialog box. After that we save/change the tag content. That does not mean we save all tags in the selected files.
Anyway I prefer "ok" over "edit" (even if it is no verb).
"OK" is right choice I think
maybe this is to my workflow: I always use the extended Tags dialog box, not the tag fields on the left hand side.
"ok" is better. 
Can somebody please give a clear description, where the mta files have to be located on a Mac. I read about this elsewhere, but the required folder is not in my User Library folder. When I create it myself, it is not working. So far I am using the Trial version, but when I have it working I will buy it.
Yes, I can give a clear description: the Mac version has no mta files, it's a format that is used in the Windows version and not available on the Mac.
Instead, it stores the preferences (including action groups) in macOS User Defaults which you can read via Terminal.app and the command
defaults read app.mp3tag.Mp3tag
So, if you're using for a quick and easy way to import your actions from Windows, it's unfortunately not possible. See also FAQ → Can I import data from Windows.
I've now added support for importing actions from Windows with v1.4.4.
Now, we can create multiple actions in text file and add it to mac version
Where are the instructions to import actions Windows with v1.4.4?
Vielen Dank! 
I was stymied in trying to find this when I fired up mp3tag v1.4.4 without yet selecting any mp3 files to edit. In that case, the "Action" menu items are all greyed-out. I.e. one cannot import action groups unless and until you are editing at least one mp3 file. Something to consider changing?
