How to include header row in export settings?

[ohrenkino]

@man_like_marv

I've tried searching but can't find anything.

Have a look at the documentation:

Export Tags to Text Files

Export to Text Files Mp3tag lets you export tag and file information to text-based formats via File → Export or ⌘E. You can use any text along with the available placeholders and scripting functions to define the export format. Mp3tag applies this format to each selected file, generating a textual representation for each one. The resulting export file contains one line of output per file. You can define a format string used to create the export filename at Preferences → Export. Export to Clip…

It says that you get 1 line per file. So there is no way to get a single line as a starter.
Perhaps you could add
$if($eql(%_counter%,1),'Cover;Filename;Artist;Title;Genre;Grouping;ContentGroup;Publisher;Conductor;Comment;Year;BPM;Key;Album;CreatedDate;Extension;FileSizeBytes;Length;Width;Height;Bitrate$char(13)$char(10)',)
to get a line only for the first file.