Framer has some restrictions in creating custom form. Here I have Explained How You can use a custom editable template form in framer Free! It will take you maximum 1 minute to setup.
1. Create an account on www-getmagicform-com
2. Create a new form
3. Select the template page on top nav bar
4. Choose a form template and remix it on your website
5. Edit form
6. Copy the form id you created on Getmagicform website and paste it.