In the United States, to start a town one must amass a somewhat ample following and have a decent reason to start the town. One must then approach the state legislature and they will vote on whether or not to issue your town a charter for incorporation to be recognized by the state. If your town grows, they will build schools, post offices, and government offices.

Sure you can. That's how practically every town in the world got started!

Throughout the course of history, towns usually come into being in stages:

• A small group or family builds houses in a place and starts living there
  
• More close friends and relatives decide to move to the area to be near their loved ones
  
• The people decide to start some sort of business to deal with people in neighboring areas (or even the small community itself)
  
• More distant friends and relatives move there to get a "piece of the action" and a good place to settle down
  
• The people open up one or more shops or stores and start farming to support themselves and make money from trade
  
• Strangers begin to take an interest in the growing community and move close by to neighboring lands
  
• Trade between the original settlers and their neighbors grows as the neighbors open shops and start farms of their own
  
• As trade begins to grow and profit potential gets higher and higher even more people migrate to the area
  
• Land begins to be swapped and sold amongst the people in the area and new houses spring up all over the place
  
• Larger influxes of strangers come to the area to settle down, build new houses and farms, etc
  
• Many many new shops open up to sell goods and services to serve the growing population
  
• This process continues until the population begins to become significant
  
• Eventually someone will be elected to lead the community; whether its a governor, religious leader, patriarch/matriarch or unofficial mayor or sheriff
  
• They apply for a charter of township to become recognized by the state, thus becoming an "official" town
  

That has happened millions of times in human history. And towns and even entire cities can also be planned. Washington, D.C., for example, was a planned city. To plan a town you just have to have the money and resources (e.g., land).