Here is how you can PERMANENTLY delete a form (please note there is no way to restore a deleted form):

1. Log in as an admin user.
   
2. Open the form you wish to delete by selecting it from the form list.
   
3. Click the edit button (pencil icon) in the top right corner of the form details screen.
   
4. Click the red "DELETE FORM" button in the top-right corner of the Edit Form Settings screen. 
   
5. Confirm delete by clicking either Yes or No.

*Note: Deleting a form does not delete the data layer that is created when the form is made. To delete the data source/layer, you need to go to the "Data Source Admin", and click "DELETE".