Click on the Settings option on the right side of the toolbar and then go to Organization settings. Click on a link Invite your colleagues.
You can invite an unlimited number of colleagues into your organization, no matter your current plan!
When a new window shows up, type in the e-mail address of your colleague you want to invite.
Select the Role of your colleague (Admin, Viewer, Editor). If you want to invite more than one colleague, click on the Add button. You can invite your colleagues only if you are an Admin or a Creator.