Whitelisting
Whitelisting is the creator granting a brand advertising access to run paid promotion from her handle, so ads appear to come from her. It borrows her identity, not just her content, and needs explicit scope: duration, spend visibility, audience targeting limits, and an end date. It is priced as usage on top of any organic fee.
Worked example
A brand whitelists a creator's account for eight weeks to run her review as an ad — the contract lists the period, the ad account, and an added fee.
Related: Dark posting · Usage rights
Full context in the guides, or measure it yourself with the free tools.