When you need to edit a form maybe because you want to add a new required field or remove a field that is no longer used, click the 'Edit' button the desired form.
Edit Form
You will see a form to edit an existing Form Builder. For example, in the "Form Registration" form, update the First Name field to Name and Field Last Name to Phone Number by clicking 'Config' button and updating label, such as image bellow.
Edit Existing Form
If you're done, click the 'Save' button, then you will see form metadata, and click the 'save' button.