The process of the postal service?

Question

Can someone explain the process of the USPS? When you mail something, does it go by plane? By trucks? Cars? Does it goes trhough stations or something to be certified? Please be specific.

Answer 1

it depends where its going (locally),across the country, in the same state? (probably by truck)
international, and what class of service, express mail? priority mail
global priority? global express?

I heard that the postal services uses the services of Fedex
for their priority packages and international services..
thats why you usually see a fedex drop box at most major

post office)