For any need-based (particularly federal grants and loans), you need to complete the FAFSA before 3/1/2018. It’s live now and very easy to fill out with 2016 tax return and W2 data. See the following link for more details:
https://onestop.umn.edu/finances/apply-financial-aid
FA letters are usually sent out sometime in March. Some colleges may also have need-based college-specific scholarships requiring a separate application. The following link can send you to descriptions of all scholarships available: