I downloaded my USA registration yesterday. Need to fill it out and send it off so I can vote in mid-term elections. I did find a post office while on my walk by the river. The only post office I believe in Siem Reap. there are no nail pick up like America. I have seen so me post boxes around town, but have no stamps. So off to the Post Office. I have never sent anything by mail since I have been here in Siem Reap, Cambodia. I also have never received mail. I have a virtual mailbox set up from California. They notify me if there is mail. I review it and if I want the contents I have it scanned and sent over email.
Hope it works.