Registration limits
The Registration Limits panel in the form editor controls when a form accepts submissions. All checks are enforced server-side, so a stale browser tab cannot bypass them.

Maximum registrations
Set Maximum registrations to cap how many submissions a form accepts. Once the count is reached, visitors see the closed message instead of the form.
The capacity check counts saved submissions, so it requires Save submissions in WordPress to be enabled. In webhook-only mode there is no local count and the cap is not applied.
Open and close times
Registration opens and Registration closes take a date and time (in the site's timezone):
- Before the opening time, visitors see "Registration opens on …".
- From the closing time on, visitors see "Registration is closed."
Both are optional and can be combined with the capacity cap.
Closed message
By default LocalForm shows a message matching the reason (not yet open / closed / fully booked). Set Closed message to replace all of them with your own text.
Developers
The final decision goes through the localform_is_accepting filter, so you can add custom rules (e.g. members-only windows).