To apply for an OSCA (Office of Senior Citizens Affairs) ID, you need to visit your local OSCA office. Bring necessary documents such as a valid ID, proof of residency, and your birth certificate or other identification to verify your age. The staff will guide you through the application process, which may include filling out a form and submitting your documents. Once your application is approved, you will receive your OSCA ID, which entitles you to various benefits and discounts. For the most accurate information, check with your local OSCA office or visit the official website of the Department of Social Welfare and Development.