To apply for Supplemental Security Income (SSI), you must apply in person at your local field office or by phone. There is no online application for SSI. Social Security will ask you several questions to see if you qualify, such as household income, number of people in your home and any assets. If you qualify under their “non-medical” rules, they will ask you about your impairments, medical treatment, when your disabilities began, etc.
To apply for Social Security Disability Insurance (SSDI), you can apply online at ssa.gov, in person at your local field office or by phone. There is also a checklist online that details information you will need when you apply.