How does the military service exemption work if you're working?

There's no automatic exemption from military service just because you're working in Brazil. What you can do is request a deferment if you have a formal job, but that just postpones the draft, it doesn't exempt you. The actual exemption only happens for specific reasons like serious health problems, being an only child of a widow, or really particular situations where you need to provide proof at the military board. If you're unsure about your case, the best thing is to go straight to the military board in your area and explain your situation, because each case is analyzed individually.