When I registered with the USCF, they emailed me with the sentence, "If you are a chess.com member, you can use your PIN to play US Chess rated chess on chess.com".
How do I link my USCF ID with my chess.com account?

The official USCF club here is https://www.chess.com/club/uschess - the profile has instructions on how to apply.
An answer would be helpful. Thanks.