If you are applying for Financial Aid and you are US Citizen you will fill in the FAFSA. Here is lots of information
The official five part series.
Every state has their own rules; and each institution has its own implementation. Instate Angels aim to help you navigate this.
Especially worthwhile to check out Reciprocal agreements whereby one state gives another state resident in state tuition and vice versa.
Every college must publish the NET PRICE it will cost students (that is the Cost of attendance - grants and scholarships you might receive). Quickly find a specifc university NET Price Calculator here.