Definition
Under FTC guidance, influencers must clearly disclose when a brand pays them, gives them free products or has another connection, in the post or video itself.
What it means
The Federal Trade Commission's Endorsement Guides say that when there is a material connection between someone who recommends a product and the brand, such as payment, free products, a discount, a family or business relationship, or an affiliate commission, it must be disclosed clearly and conspicuously. The disclosure should be in the endorsement itself, hard to miss, and easy to understand, using plain words such as "ad" or "sponsored" and the platform's paid-partnership tool. A disclosure only on a profile page or buried among hashtags is not enough. In videos and live streams it should be said and shown. Brands are also expected to monitor the people they work with. Honest opinions are still required: you cannot claim to have used a product you have not tried.
Example
A fitness creator paid to post about a protein powder writes "Ad: I'm paid by this brand" at the start of the caption and says it at the start of the video.
Illustrative numbers only. Your situation will differ.