Powershell uses the abstraction of Providers to provide a common interface into datastores. These seem to stick with the common noun "Item", so you can get a complete list with man *item*. If you know another way to copy and otherwise work with data from a store, you might as well use it, but using the cmdlets provides a better "learn-once, use-often" approach. In your case you could:
Copy-Item test.txt -Destination \\dest-machine\share
Copy-item also supports the -Credential parameter if you need it.
