If you are an owner or admin (Enterprise only), you can add new members or guests to your team whenever you need.
To add new team members or guests:
Sign in to your account and, at the top of the page, click Team.
On the right side of the page, click the large plus button.
Decide whether you want to invite a member or a guest, and click Invite.
Type their email address and click Next.
If entering multiple email addresses, you must separate each address with a comma.
To the right of their email address, click the drop-down to make the person an Owner, Member, Guest, or Admin (Enterprise only).
Your invitations are now sent, and you can click Got it to return to the Team page.
To let people join your team without requiring an invitation, you can set up Open Enrollment. With Open Enrollment enabled, anyone can sign in to the team by using an approved email address—i.e., an email address from an email domain that a team owner has previously approved.
For more on teams, check out these related articles: