I'm trying to do a problem write-up for my quantum mechanics class and would like use Mathematica since I'm going to be using matrix mechanics and it'd seems like the best way to write a lot of matrices, in line, very quickly. However, I'm worried that the default margins are too large to print out a paper. How do you change the default sizes of the margins? Bonus points to answering the following:

Are there any sites that give a comprehensive guide to text editing in mathematica?

Is there any other software that might be better suited for mathematical writing? My professor is crazy about LaTeX but I don't really know where to start with that. (I'm on Windows 10 btw)

Thanks in advance!