If a simple signup has reached capacity, you can give people the option to reserve spots with a waitlist in case they become available.
Waitlists are only available for Simple Signups.
From the Selection types tab under your signup's Configuration tab, check the box to enable the Waitlist for selections.
As people register for the signup, the Registrations number will increase. If someone already selected the waitlist, the box will be grayed out.
As people sign up, they will be added to the Waitlist tab. If spots become available for their chosen selection(s), you can promote them from the Waitlist to refill those spots.
Select a registration on the Waitlist tab to promote it.
On their registration, click Promote to move the registration from the waitlist to active.
When you promote a registration, the registration contact will receive an email about their registration.