You can invite a user to a space even if they are not yet registered in flip, and add them to one or more groups:

1. Click Invite on the top toolbar.
2. Enter one or more email addresses.
3. Select one, several or all of the teams you want to add the users to.
4. Click Invite — invitations to the space will be sent to all the users you specified, and once they sign up, they will appear in the corresponding teams.