How to import parts of the filename into the tag (Filename to Tag)?

I want the title of the name without the number, is it possible?

Yes, provided you have a pattern.
Enter
%dummy% for the parts of the pattern that you do not want to import.
E.g.
01 - Yellow Submarine
and you want to leave out the "01" then enter
%dummy% - %title%

But if I add "%dummy%" and then "%title%", I get: "%dummy% %title%", it copies the title and the number.
"%dummy% - %title%" with the "-" is not possible. "OK" is grey.

Without showing us the EXACT filename, it is not possible to help you.
The format string has to match the pattern that can be found in the filename. If there is no match, then the OK button is disabled.

Thanks for the reply!
Filenames are:

  1. Piano Concerto № 9 Es-Dur K. 271 «Jeunehomme» – I. Allegro.flac
  2. Piano Concerto № 9 Es-Dur K. 271 «Jeunehomme» – II. Andantino.flac
  3. Piano Concerto № 9 Es-Dur K. 271 «Jeunehomme» – III. Rondeau. Presto.flac
  4. Piano Concerto № 20 d-moll K. 466 – I. Allegro.flac
  5. Piano Concerto № 20 d-moll K. 466 – II. Romance.flac
  6. Piano Concerto № 20 d-moll K. 466 – III. Rondo.flac

It looks like the separator is the full stop.
So the mask could like this:
%dummy%. %title%

This works perfectly!
Thanks again.