To apply for a Pag-IBIG calamity loan, first ensure that you are a qualified member and that a calamity has been declared in your area. Gather the required documents, including your valid ID and proof of income. Fill out the loan application form, which you can get from the Pag-IBIG website or your nearest office. Submit your application along with the required documents, and wait for Pag-IBIG to process your request. For detailed guidance, check the official Pag-IBIG Fund website or consult their customer service for assistance.