The advertising feature (‘Promote’) on TikTok is only available for videos that use sounds from the official commercial music library.
Music delivered through us is licensed music — this means that even if it is your own music, it cannot be promoted using this feature.
If you are an artist with a label, you can create your own TikTok Ads Manager account through that label. With this account, you can then place targeted advertisements to promote your own licensed music.
Currently, there is no other way to promote your licensed music directly through the normal ‘Promote’ feature.