You must file an application to receive benefits.

In addition to meeting other requirements, you must file an application to become entitled to benefits. If you believe you may be entitled to benefits, you should file an application. Filing an application will— (a) Permit a formal decision to be made on your entitlement to benefits; (b) Protect your entitlement to any benefits that may be payable for as many as 6 months or 12 months (depending on the type of benefit, as explained in § 404.621) before the application was filed; and (c) Give you the right to appeal if you are dissatisfied with the decision. [44 FR 37209, June 26, 1979, as amended at 46 FR 47444, Sept. 28, 1981]