First you would have to be in a state that issues medicinal card. Second, find yourself a corrupt doctor which can be paid of OR spend some money and get a fake one.

A license does not exist.
A State allowing MMJ may have a registry card. I believe that a question like this gives all the marijuana haters a reason so say everyone with a Dr. for a recommendation for marijuana is just an abuser in disguise. You admit to having no illness. So there is no easy way for you to obtain a Dr. recommendation. Many States include wasting / cachexia as one of the chronic debilitating conditions for people dying because they can’t hold down food. Questions like this are also the reason some States now require ANY patient under 21 to receive 2 Dr. recommendation.

Depends on what state you’re in.

For better or worse, in some places like California, I’m aware of people not having significant problems getting them for virtually any excuse like insomnia or headaches or cramps, etc.

No idea if they might start cracking down on things though, since it seems to be getting pretty far away from the things like people in chemotherapy or with AIDS or bad burns for whom it was intended.

Of course you can go to many doctors and get virtually any psychiatric medication at your request these days too. That may be an even worse problem.