Using Convert → Filename - Filename, you can rearrange parts of file names by marking up to nine parts using a pattern over the file name and rearrange them using a new file name pattern.

The Old filename pattern splits the file name in several parts. It is built of standard text (e.g., Music and delimiters like -, _) and by placeholders that denote the reusable parts, starting at %1, %2, up to %9.
You can mark directories via the backslash character \ within the pattern string.

The New filename pattern uses the previously defined parts (accompanied by optional standard text) to resemble the target file name.

If you use the backslash character \ within the new filename pattern, Mp3tag creates new directories below the current working directory for relative paths or at the at an absolute folder location if it starts with a drive specification, e.g., D:\Music.

You can use Scripting Functions when defining the new filename, e.g., $upper(%1).