You can apply for Social Security Disability Benefits by proceeding to your local SSA office or by applying online. The online process is far more convenient but you will not have the assistance of a SSA representative. To apply online, proceed to the primary SSA website, https://www.ssa.gov/benefits/disability/ You should have the names and addresses of your medical providers and recent employers available before you begin the process.
Alternatively, you can visit your local SSA office to apply for benefits. See SSA Office Locater. https://www.ssa.gov/locator/ In some cases you may want to call ahead of time to see whether you can schedule an appointment. The waiting time for in-person services can vary substantially depending upon the traffic at your particular office.