All instructions writers wrestle with these terms. Just remember that instructions should be absolutely clear, without ambiguity. "Preferred" can be ambiguous. Does a "preferred" printer stay that way? Are you referring to a "preferred" printer, or just a printer to use now?
Select the printer to use (for whatever you are doing).
Avoid "desired" and similar words that imply emotional choices.
"Select the printer to use" is about as clear and concise as you can be. Most importantly, you may have to explain what a "preferred" printer means, because that's the word in the software interface or existing documentation:
"Select a printer from the Preferred Printer list. Documents will be sent to this printer unless it is not available. In that case, documents will be sent to the Secondary Printer."
When graphical user interfaces were new, there were prescribed terms: You select an object, text, or item to be the target of an action. Selection is a "ready" state. Then, you choose a menu command or click a button to apply the command to the selection.
GUIs have evolved, and newer writers don't always observe these distinctions. If you haven't done it, check out the Apple and Microsoft style guides for technical communication.
And this, for all the right names of things in the Windows UI: