I am assuming that this is a first time passport for an adult. There are additional requirements for minors.
To get a new passport, you first complete Form DS-11. You won't sign it until asked to do so by an authorized passport agent. Take the application, evidence of citizenship, evidence of identity and two passport photos to the nearest passport application acceptance facility. There are more than 9,000 locations in the U.S. Many post offices are authorized to receive passport applications.
You also need to take your Social Security card with you and show it to the agent. A $25 execution fee is paid to the agent and a $75 passport fee is paid to the State Department and sent with your application.
Regular processing takes 4-6 weeks. It can take more or less time depending on the demand at the time you submit your application. You can request expedited service which cuts the processing time down to 2-3 weeks. There is an additional $60 fee for this service.
Applicants who need to obtain a passport in 2 weeks or less can make an appointment at a regional passport agency by calling 1-877-487-2778. If you need your passport quickly but cannot visit the regional agency nearest to where you live, you can contract a private expediter to submit the application for you. Of course, the charge a fee for this service.