How added Music labels?

Hi
To edit mp3 tags, I use TagScanner and Mp3Tag (I write artists/covers and other myself)

After adding a music library, music labels are registered on many albums. Where do they come from if I have checked only local tags?
I have to manually delete everything

For all I remember, there’s no only local tags option – just a prefer local metadata. Plex will still try to match your albums and to provide additional information if missing in the embedded tags.