If you forgot to add some contacts to the invitation and would like to send them a survey invitation as well, you can create a new invitation for the missing contacts.
You need to create a new invitation for the missed contacts because you can’t add new contacts to an existing, already-sent invitation. Once you’ve created the new invitation and added the missing contacts, you can send it to them. All respondents’ answers will appear in the same survey results and report, even if the invitations were sent separately.