1 You can obtain a copy of the application online at http://www.ssa.gov/online/ss-5.html. 2  Prove who you are by providing a recently issued official document, such as a driver's license. 3  Provide proof of citizenship [source: Lawyers 4  ]. Mail your application to your local Social Security office, or bring it in in person. You can obtain a copy of the application online at http://www.ssa.gov/online/ss-5.html. 2  Prove who you are by providing a recently issued official document, such as a driver's license. 3  Provide proof of citizenship [source: Lawyers ].