Senior citizens in the Philippines can apply for PhilHealth coverage by visiting the nearest PhilHealth office or registering online through the PhilHealth website. You will need to present valid identification and any necessary documents, such as proof of age or residency. It's important to check the specific requirements for seniors on the PhilHealth official site, as they may vary based on your situation. If you're unsure about the process, you may want to consult with a local PhilHealth representative for guidance.