If you are an administrator in a project you can add new members. As a member of a project, by default you are not able to add new members, but an administrator can give access to invite members.
A new member can be added by going to:
“Members” (left hand menu)
Invite member
type in their email address(es)
select their role in the project, and which team (optional)
+Add
Optional message=>Send invite(s)
