Invention

gimme yr blueprints and I'll patent them for you...trust...

The Patent Office (or whatever the equivalent bureaucracy might be called in your nation of residence) will no doubt supply you with the proper forms and vague instructions. One major difficulty is doing the requisite patent search to determine whether your idea has already been patented by some other hapless Joe who spent his own life's savings and put a second mortgage on his abode to do as you now intend to do, all to no avail.

Unless your idea is so fundamental that a whole industry could spring up around it, or every company in a given industry would be required to license it from you, then my own advice would be to document you idea to establish your precedence and then shop it around to some company that might conceivably be able to capitalize on it. It's a cheaper way to get screwed.