If you are working with web documents on a regular basis, than you have surely come across XML formats before. There are myriad forms of languages out there but recently XML has jumped to the forefront. I find that I work with it on most of the web things I am developing, and that there is a real need for more people to understand it, with the advent of the technological age.
I find that frequently I need to provide a more dynamic interface to folks who are interested in reviewing my code progress on whatever projects I am developing, which is why it is often convenient to convert XML to PDF format. Luckily there are many programs that are suited to do just that thing, and you can find these online in many forms. I suggest getting a good program with a solid interface, so that you can select the way that you want your documents to be formatted into PDF. When done incorrectly, converting XML to PDF can be a bad idea, because the code may end up somewhat warped and harder to understand than it began, but these problems can all be solved with a good conversion program.