Trikko waiting list - customer email form

Does anyone know how to make the "Password ____Enter" and "Join Waitlist" button? When you press on the "Join Waitlist" a dropdown field appears where the customer enters their email and name...

Check this website out to better understand what I'm talking about :
https://trikkobrand.com/password

Maybe it's a plugin/app? or code? or a theme?

If you know, your help will be much appreciated. Cheers x