My friend signed up without my link. Can I add a code afterwards?

Calsa connects an invitation when a new account is created during a visit started from that link. There is no code field to add it afterwards.

If your friend has already created an account without the link, do not ask them to create a second account or use another email. If they did open your link and the invitation seems to be missing, contact support so we can check what happened. This does not guarantee a reward.