How did florida become an american territory and what did that mean for residents of florida

Florida came under U.S territory after Spanish minister Do Luis de Onis and the United States Secretary of State John Quincy signed the Florida Purchase Treaty, where Spain agreed to cede its old province of Florida to the U.S. at no cost. 
After the end of the India war, many people settle and made Florida there home, developed towns. Therefore, people wanted a State, where they could elect their governor, send senators and representatives to Congress and take part in presidential elections. They would also enjoy many other privileges that were not allowed in the territory.