You can use this option whenever you want to remove a generated form. By selecting the delete form, you can completely take down the form page in case it is disabled or expired.
To delete forms;
Go to "Forms"
Click on forms, at the top right of your board, it shows all the forms you have created.
Click on the Option Menu
Click on the three vertical dots by the right of any of the forms created.
Click on "Delete Forms"
You can completely remove a form by clicking the "Delete option" in the options menu.
There you go, your form has been deleted.