UGC (user-generated content, in trade use) is content made to look like a real person talking about a product, usually so the brand can run it on their ads and organic channels.
You may never post it on your own grid. Followers may not matter. Craft and turnaround often do.
A UGC creator is someone hired to make these assets. The brand is usually buying production and a licence to use the work, rather than guaranteed reach from the creator's audience.
UGC vs influencer post
Influencer-shaped work borrows your audience. UGC-shaped work borrows your ability to sound native. Many creators sell both. They should not share one price.
Usage
UGC without a usage window is how a ₹15,000 file becomes a year of ads. See usage rights.