File Shortcuts

I know this question must have been asked before, but I just spent 20 minutes searching using 5 different terms, and I can't for the life of me find the answer, so my apologies there.

I can't believe I've been using my Mac 6 months so far and don't know this yet.

When I'm working on a long paper for school I like to have it saved to "Documents" and have a shortcut to this on the desktop. However, I've discovered just dragging the file to the desktop takes it out of the "documents" folder, and that duplicating the file means I have to save it to each place separately.

How can I just create a shortcut to a file in "documents" on the desktop so I can just save to "document" (or desktop, for that case), and have the latest version each spot whenever I need it.

Is this what Alias is for?