Setting up private modules in Go allows developers to host packages in their repository without making them publicly accessible. To set up a private module, you can create a directory, initialize the module using `go mod init`, commit, tag, and push it to a repository like GitHub. Fetching a private repository requires authentication, which can be achieved through local environment variables, GitHub Actions, or Dockerfiles. By setting the GOPRIVATE environment variable and configuring Git to fetch via SSH instead of HTTP(S), developers can access their private modules.

Source: https://dev.to/patricia_chebet/setting-up-and-utilizing-private-modules-in-go-a1m