How to add a partner agency
In your Business Manager, go to the "Partners" section.
Add a partner simply by copying and pasting their Business Manager ID.
When adding them, you can select which assets from your Business Manager you want to share with this partner (ad accounts and TikTok accounts, catalogs, pixel, etc.).
Info
For reference, you can find this ID in the “Settings” tab, under the “Business Center Information” section.