How can i invite people to help.edit my game?

does anyone know how I can invite a person to a game and the person helps me create design and stuff like that?

only indie or up users can invite people

Indie accounts can invite users into a group in there profiles. The indie user can invite anyone, including free users. They accept the invite in their profiles too.

how do you join a team invite

On, click on your name in the top right and click profile.
If someone has sent you a team invite, it will show up there.