what do humanity need to invent a machine that can create any thing we think about?

A number of machines and sciences we take for granted was engineered off of Star Trek gadgets.

A 'Replicator' could do what you suggest in theory. Although they weren't specific on whose doing the test. Scientists have created one. They managed to make a cup of water out of thin air. The water not a cup. The rub is the energy needed to create just that was too much to make it practical for every day use. One day maybe.

You have to have a device that would have access to all the needed materials in atomic form and somehow assemble them into the form that would make the things you wanted - lots of technologies that don't exist....

3D printers are arguably a step in that direction. So keep the faith we could get there. But considering how terrible some people are out there it may be a case of be careful what you wish for.

3D printers are somewhere there I think

Sounds like the matrix

So you are thinking on lines that this machine would not require any resource? and would create things out of thin air, like a magic?

A machine that could make sandwiches cars and houses effortlessly couldn't create meaning, purpose and fulfillment.

It would probably destroy those things.

That idea would make for a good book and would show how things would go wrong as human nature gets involved. Like all positive ideas there will be a dark side.

That would be way to dangerous, some would create evil things.

It isn't I think, possible and I don't think, by in large, it would be good for humanity.

You'd only need one, then it could manufacture endless copies of itself.

Then what is the purpose of your existence?

Even if we could, is it really a good idea?

Because people are thinking with their pocketbooks instead of their brains. If humans stop creating then our sole unique trait will be lost and we will die.

You are thinking of a star trek replicator.