Go to the Users settings page from your navigation bar.
Here you'll find a list of all users. Click on the green Invite a User button.
Fill in the user's email address and his user role: Publisher, Writer or Guest writer.
Guest writers can only write new stories or ones they have been invited to. They also don't have access to statistics.
Writers can access all stories, including statistics. They can only see the campaigns they are assigned to.
Publishers are able to do everything that writers can and in addition publish stories and manage destinations. They also have the ability to add other users and change account settings.
You also have the option to not send out a notification email to the user (if unnecessary). There is also a field where you can add a personal message explaining why they have been invited.
Your teammate will receive an invite in their mailbox (if chosen) and will be able to login to your company's account.
You can also invite a user via a story.
Select an existing user or create a new one.