Boosting amplifies a creator's existing post from your ad account while keeping the creator's handle on it: the format platforms reward most.
How permission works per platform:
Meta (Partnership Ads): you request permission; the creator approves in their Artec app. The request expires after 7 days if they don't respond, and you can re-request.
TikTok (Spark Ads): the creator supplies a Spark code from their TikTok app; pasting a valid code is the grant.
The creator earns a commission on what you spend boosting their post: you'll see spend and the creator's accrued commission right on the boost button.
On CPM deals this stays fair: boosted views don't inflate CPM pay: CPM keeps counting organic views only, and the boost commission is paid in parallel.