Simple if that mail man has a route that includes his house then he delivers his own mail. However that is highly uncommon. Otherwise whichever mail man that has the route that includes his house...
Firearms can legally be mailed within the restrictions of the Postal Service. Ammunition and many other explosives cannot be mailed.(see the related link)
First you move your mouse on top of the word "Hotmail" at the top left corner and then it will show you a menu with the word "Inbox" when you click on it, it'll show you your mail.