To access the administrative functions, click on the 'Settings' button and choose 'Organisations'.
Choose the existing organisation or if you want to create an organisation for the new user, click the Create button.
Once you click on the Organisation, you will then be able to see the list of users, their email ID, their level of access, and the date and time they were created on. If you have Super Admin access, you can Suspend, Delete the user or even transfer them to a different organisation under your account.
On the same tab, you will be able to Invite a new user using the 'Invite Admin' button, you would have to mention the email ID, and an invitation for this account and for this organisation would be sent to the user.