Your Meta Artist ID is a unique string of numbers that identifies your Artist Page across Facebook and Instagram.
Here's how to find it:
Head to Meta Business Suite and log in with the account that manages your artist Page.
Click Settings in the left-hand menu, then select Pages under Accounts.
Your Meta Artist ID is the string of numbers shown underneath your Page name, as shown below.
Alternatively, head to your Artist Page on Facebook and click your Page name at the top of your profile to open a pop-up. Scroll down and click Transparency and Privacy Policy. Your ID is also listed here.
Make sure you provide your Meta Artist ID on your Artist Dashboard to make sure your music is always mapped to the correct artist profile.