The short answer
A rate card is a document listing a creator's pricing for different types of content or partnerships: a feed post, a short video, a full campaign. It is usually shared directly with a brand during early conversations, and sometimes included in a media kit.
Why having one speeds up negotiation
A creator with a clear rate card can respond to an inquiry with real numbers immediately, rather than working out pricing from scratch for every new conversation. It also signals a level of professionalism that tends to be taken more seriously by brands used to working with established creators.
A rate card is a starting point, not a fixed rule
Real negotiations still adjust from a published rate card based on usage rights, exclusivity, or overall deal size. The card sets a clear baseline and speeds up the conversation. It does not remove the need for judgment on a specific deal.