You can manage the attendees without a payment mechanism by using the RSVP tool.
RSVP enables #
First of all, go to Eventin -> Addons and enable the RSVP modules.
Auto verification Email #
From Settings -> RSVP -> General Settings, you may enable auto verification email for RSVP events. The email body can be modified in whatever you like.
Auto Confirmation Email #
You can enable auto confirmation for the RSVP events from Settings -> RSVP -> General Settings. You can also edit the mail body as you want.
User Allow to Form #
You can allow users to access the RSVP form with login also without login.
Attendee limitation #
You can set the attendee to how many attendees need to start the event.