Having decided what to provide as user documentation, the next question is where to provide it. The answer is: put the documentation in the same file as the module or application itself (i.e., in the relevant .pm or .pl file).
The other common alternative is to put the documentation in its own separate .pod file. This is possible because perldoc is smart enough to look for POD files as well as source files when searching for documentation. The problem is that this approach works only if the appropriate .pod document has been installed along with the module or application, and has been installed somewhere inperldoc's search path, which is unlikely.
In contrast, if the user documentation is placed directly in the appropriate .pm or .pl file, it will automatically be available anywhere the module or application itself is.