I live in the U.S.?
Go to the Post Office and get an application. You mail away your most recent passport with two new pictures of yourself and a check much larger than you think your government should charge you for such a service, and then within a month or so, youll receive a new your old passport back with a corner chopped off accompanied by a new passport. If youre applying for a new passport, youll need to meet in person with someone with appropriate documentation to show you are a citizen.