How do I write the member's name in the message?
Use the placeholders in the message window; the member mention, server name and member count are filled in automatically.
Is the image card paid?
No, the image card in the channel message is free. Adding an image/GIF to the DM welcome is Premium.
Is there a thank-you message for boosters?
Yes. With /boostmessage, a thank-you card goes to boosters in the channel you pick.
Does it work with the registration system?
Yes. If you use the registration system, newcomers get the unregistered role and the welcome message is sent too.