Creating an organization is a function under Settings. So, you need to find Settings in your GitHub account, as shown in the following screenshot:
One menu item in Settings is Organizations. You can create an organization in two different ways. You can either turn your user into an organization or create a separate organization. We will create an organization and not turn the user into an organization, as shown in the next screenshot:
Once the organization is created, you can invite users to become members. It is also possible to add outside or external collaborators.