If you have never created an organization in GitHub, you can find instructions on how to do that here. Creating an organization is easy and free of charge.

Once you have created your new organization, you can import your existing repository into your new organization. GitHub has an article explaining this process here.

Select *
If requesting to add your existing organization, place your Organization URL in the next box.
If you're not importing an existing Organization, place what you would like it to be called in the next box.
Name should follow the pattern "txst-<dept>" or "txst-<dept>-<subgroup>" (e.g. "txst-itac-msrv")