You can create a new organization by either setting up a new organization or converting an existing personal account into an organization.
About organizations
Organizations are shared accounts where businesses and open-source projects can collaborate across many projects at once. Owners and administrators can manage member access to the organization's data and projects with sophisticated security and administrative features.
Creating a new organization from scratch
Create an organization to apply fine-grained access permissions to repositories.
Converting a user into an organization
You can convert your user account into an organization. This allows more granular permissions for repositories that belong to the organization.
Permission levels for an organization
After you create an organization, you should give Owner permissions to a small group of people who will manage the organization account.
Adding people to your organization
You can make anyone a member of your organization using their GitHub Enterprise username or email address.
Removing a member from your organization
If a member of your organization no longer requires access to any repositories owned by the organization, you can remove them from the organization.