To apply for senior citizen discounts online in the Philippines, you typically need to visit the official website of the Department of Social Welfare and Development (DSWD) or your local government unit. They often provide forms and guidelines for online applications. Make sure to have your valid ID and other required documents ready, as these may be needed to verify your status. It's also a good idea to check with your local government office for any specific procedures they may have. Always ensure you are accessing official government sites to avoid scams.