Hi, I´m designing an app for our programers. As a designer I need to know what kind of fonts I can choose from. The app is going to be designed for Mac, PC and Linux.

Can I embed fonts or is this not recomended?
Do I have to use systemfonts in each OS, and what are the system fonts?
(Remember the app is also designed for different versions of each OS).

What are my limits and what can I choose from in the fonts area?

Any help would be nice!