Hi @bsolana,
I am not sure if you are you talking about when purchasing a webinar product on when using the plugins registration forms. But I don’t think that actually matters, because in either case the plugin is just providing an outlet to register for a webinar through a form. The plugin can’t register people for webinars they never signed up for, that’s against GoToWebinar’s rules. However if you are talking about pre-filling the form to make it quicker to register for a webinar, well this can be done in 2 ways. If you are talking about a webinar product then if the person has a WooCommerce account their details will be pre-filled in the billing area and using the quick copy button in the plugin these details are copied over to the registration form so that’s pretty easy. For standard registration forms on your site if the user is signed in it will actually pre-fill their name and email into the form so they don’t need to enter this every time.
Thanks and I hope that helps,