In general, we require users to register with an external account like their Google, LinkedIn, ORCID or Mendeley account. However, as part of the process of requesting a service, the sign up step, we also allow to proceed with just a name and email address. We consider this an "incomplete" profile as it is not validated and linked to an external authentication provider.
You received an email including the request to "complete your profile". There is a link in there. Click it and follow the procedure. You will have to authenticate still using any Google, LinkedIn, ORCID or Mendeley account.
If you missed the email, go to https://www.peerwith.com/emaillogin and follow the procedure.