Do I need a credit card to start a link in bio?

Not on ItsMyLinks. Signing up takes a name, an email, and a password. There is no card field because there is nothing to charge: the page is free, and it stays free. Some tools ask for a card to start a trial and bill you when it ends. ItsMyLinks has no trial to end.

Claim your name at itsmylinks.com/join, add your links, and put the one address in every bio.