How to delete this form from my page?

The link you provide is the link of your form with custom URL. 

How to Create a Custom URL of a Form?

That is the only form you have on your account. If you want to delete your form, you can do it from My Forms folder on your account. Simply select the form and click on Delete button. 

After that form will be moved to Trash folder. You can Purge the form from Trash folder to delete it from your account. 

If I did not understood your question correctly, please explain in more details what are you trying to achieve. 

Let us know if you need further assistance.