A custom subdomain is chosen at when the organizational account is first being created. This subdomain can be used by anyone on your team as a company branded login screen.
If you don't remember what it was, follow these directions:
1. 👉🏼 Click on your Organization's Name at the bottom of the left sidebar.
2. 👉🏼 Select 'Settings' from the pop-up menu.
3. 👉🏼 Once you're in settings click on 'organization settings.' From here you'll have the ability to see your companies subdomain. All members of an organization can directly to their subdomain and sign up.