My event is today. How do I close my registration form?

You have two options that you can use, you can set the form to be disabled and you can also specify the expiry date upon which the form will be automatically disabled on this date.

These options are available under Preferences

1. First approach, manually disabling the form, Preferences->General Settings

2. Second approach, set the form expiration date Preferences->Form Limits

You can also change the message that is shown when the form is disabled