You need an SSN to get a job, collect Social Security benefits, and receive certain government services. Your employer will ask for your SSN to report your.Include service in the armed forces, self-employment, and relevant volunteer work. Have them enter their Social Security number in Section 1 as soon as they receive it. However, when filling out an application form at a reputable site, you will be asked to provide the full number. Be ready to provide it. Complete the Social Security related questions on the Form I-765, an application form you must submit to the US government for your employment application.