Because it's worn uniformly by all personnel in the Army.
usually during your first day at the army reception battalion
According to AR 670-1 chapter 28-17: Updated 3 February 2005 It would depend on which patch you refer to. "US Army" is positioned centered over the left breast pocket. The soldier's last name is...
The strength on the nation, unity and individuals serving to protect their rights.
Army officers have to buy their own uniforms because they make more money than enlisted soldiers, who do not but their own uniforms.