Use Result Limiter
to automatically close forms after a number of results have been received. Perfect for limited result forms such as; giveaway entries, party RSVPs, booking enquiries and more.
To enable Result Limiter visit the Settings page on your form, and find the Result Limit option:

This will present a number field to enter a limit. Enter it and click “Save”.

Once saved, you’ll see the ON status change. Publish the form and the new response limiter will take effect.
As soon as your form reaches the response limit, it is automatically closed and the Form Status is turned to OFF. The published form will also appear closed:

To remove the response limiter, simply delete the current value and press “Save” again. You can easily increase the limit at any time.
It’s as simple as that to keep forms locked down to a certain number of results.