Webform Content with admin approval
There is a module for that. Check Webform Confirmation.

This is confirmation module. It sends an e-mail to users who submit the webform for verification by taking the email id from the webform.
On clicking on the confirmation link in the email, the user confirms that he/she is not a spammer. It works both for both Authenticated and Anonymous users.
Also, the administrator is able to keep a track of users who have confirmed their submissions.
Optionally, you can disable sending the confirmation link in the mail which would only send a &quot;thank you&quot; mail.