To apply for Pag-IBIG membership as an Overseas Filipino Worker (OFW), you need to fill out the Membership Registration/Modification Form (MRMF) which is available online. You can submit this form at the nearest Pag-IBIG office or through the Pag-IBIG Fund website by selecting the OFW membership option. Make sure to prepare necessary documents such as a valid ID and proof of overseas employment. For more specific guidance, it's best to check the official Pag-IBIG website or reach out to their customer service for detailed instructions tailored to your situation.