What do you need for HTTPS to all autosubdomains (*.site.com)?

Question

Digital certificates

Good afternoon.
The title is the whole point of the question. I often put HTTPS
on my sites , but what kind of certificate is needed for subdomains and is it possible to install it on automatic subdomains (which the user creates himself) ... Does anyone know? Thanks in advance for your reply.

Answer 1

What does ssl wildcard tell you?