The 'familyname' field is required, meaning you must enter a value there. If you don't have a name, you can use a placeholder, e.g., '(Please fill in)' or the email address. You can then add the last name as a field in the questionnaire, and participants can overwrite the value. Important: The last name is used in the salutation, so you should no longer use the 'yve_greetings' merge tag. Instead, use a fixed text such as 'Dear Sir or Madam,'.