It certainly isn't real, nor is it limited by any real considerations. Real things are limited. There are only so many apples in America, and that's a fact and one that can't be changed from what it is, just by saying so. You can't make up houses, or apples or books simply by saying - let there be houses, or apples or books. You can't create real things just by saying so.
Real things take real stuff, like time, materials.
But money is made up in just precisely that way - money is created simply because people say so. And that's only because it is really only information. Otherwise it can't be done. A key distinction between imagination and reality is that imaginary things are as plentiful as we choose. So, in summary - money can be created at will, and indeed is, through chartered bank loans.