To apply for senior citizen benefits in the Philippines, seniors typically need to provide a valid government-issued ID, such as a passport or a driver's license, and a Senior Citizen's ID issued by the Office of Senior Citizens Affairs (OSCA) in their locality. Additional documents might include proof of residence and any other documents required by specific benefit programs. It's advisable to check with the OSCA or the relevant government agency for a complete list of required documents based on individual circumstances.