When you want to close your registration :

In the tab Manage > Event website > Website registrations > disable : Allow registrations 

At any time you can reactivate the registration.

Once the registration is closed, if a participant want to acess to the form, he will see that registrations are closed.

You can  :

  • Add text on your home page in order to precise the close of your event.
  • Event website > Customize your site > "wheel" icon next to the menu > modify Form > click on the button : Disabled in the menu.