To register for the Social Security System (SSS) online as an Overseas Filipino Worker (OFW), visit the SSS website and navigate to their online registration portal. You'll need to provide necessary details, including your personal information and a valid email address. After completing the registration form, you'll receive a confirmation email which you'll need to verify. If you encounter any issues, it's a good idea to reach out directly to SSS or check their official site for the latest guidelines and requirements.