Here are different options for limiting the visibility of your documentation if you want to make it accessible but don't want to make it public.
Internal Workspace - Share the documentation with your Postman team members by sharing your collection in an internal workspace. Only members of your Postman team can view the documentation for a collection or an API.
Partner Workspace - Share the documentation with external partners not part of your Postman team with Partner workspaces. (Enterprise and retired Professional plans only).