Paying taxes (Lagos)

Hello All,
Quick question, I plan on relocating to Nigeria soon but I am wondering what the process is like in having to pay U.S taxes. Since Nigerian companies obviously don't issue W2s (at least not that I know of), can anyone please let me know how they have filed their U.S tax returns? Has anyone experienced having to pay U.S taxes from outside the country? What was the process like? Tedious or smooth? I've checked everywhere and I can't seem to find a concrete answer. Thank you!