How to add additional form-type to be able to create more than 2 different forms on a site

I know how to override existing template of the 2 form types (contact-form and newsletter-form) that are built into Shopware 6.3, unfortunately I need more than 2 different forms on the website. So I would like to regitster additional form-type to create another form, how I can do it? 

P.S. Any news when we get custom forms? Here: was stated we probably get it in 6.3., unfortunately it is still not implemented.