Benjamin Franklin appointed the first Post Master General in 1775, but the United States Postal Services was officially created in 1794. Initially spanning from Georgia to Maine and covering 195 postal offices. By 1800 there were 903 offices.
Stagecoaches carried a majority of the mail in leather chests. The chests were opened by postal personnel at each stop. The personnel would take out the mail intended for their jurisdiction and add anything outgoing to the chest before it was sent back out on the stage. Smaller routes were covered by men on horseback who carried the mail in their saddlebags.
Stamps were not created until 1847. Before that a fee was paid directly to the Post Master for the letter, who passed on the profit to the Government. The Post Master was paid no base salary. He was paid a percentage of the profit for his jurisdiction.
Envelopes were not available until the late 1840’s. Before then people simply folded their letters inward and addressed the blank side of the page. During the Civil War when paper was not readily available people would make their own envelopes out of wallpaper, brown paper or maps. Pretty much anything they could find that was not needed elsewhere. An existing envelope was used as a template for the homemade envelopes.
In the 1830’s postal rates were often priced by distance as well as per sheet of paper. A single sheet of paper traveling up to 30 miles could cost 6 cents while the same sheet of paper traveling over 400 miles could cost as much as 25 cents. If you had two pieces of paper double that, three pieces you would triple that cost, etc. It could get costly if you were long winded.
As the post office developed mail was carried by steamboats, railroads, etc. Whatever means available to move the increasing amounts of mail at an even faster pace was used.
During the Civil War the post office was severed in two. The Post Office Department of the Confederate States was established on February 21, 1861. The post office lacked funds and stamps as well as steady personnel. The Northern blockades created disruption in service, making it hard to get mail delivered. By November 1865, after the war’s end, the Postal Service resumed services throughout all the states.