When you create a callstats.io account, you are part of an organisation and you will automatically become the administrator. If you already have an account then your default organisation name would be org-XXX (XXX is a number). You can change this organisation name anytime you wish.
You can add new members by following these steps.
1. Click on your e-mail ID on top right corner
2. select "My organizations"
3. Click on the "members" button on the right side
4. You can enter the e-mail id of the person to be invited and click "Invite"
5. The invited person will get an e-mail (Check spam folder, just in case :))
The invited person is now a member of your organization. Please note that new members cannot access the app stats until a role is assigned. You can assign an app level role to a member by reading this article.