Can customers add themselves?

Yes. You can share a sign-up link or QR code, or hand your own device to someone in person. Either way the submission waits in a review queue — nothing reaches your customer list until somebody on your team approves it, and you can mark a submission as rejected, spam or a duplicate instead. Someone using the public link also has to confirm their email with a code before the form is accepted.

The in-person route is different in one respect: a member of staff is already signed in and holding the device, so there is no email code to confirm. The public link and QR code do require one.

The sign-up section is switched off on your public page until you turn it on, and the QR code points at a short link that keeps working even if the underlying form is reissued — which matters if you have printed it on something.