There is in general no requirement for a readme.md or other dotfiles for a Go package, and unlike some other package systems there is no particular Go convention of splitting files into src/ and lib/ or mod/ subdirectories.

(Some projects do choose to put binaries in a cmd/ subdirectory, but even that convention often depends on whether there are also public-facing libraries within the module.)

In general go mod init should be enough to get you to a minimal workspace, and from there it's up to you to decide which files to create.