eAFS is an online system of the BIR which lets taxpayers submit their Filed ITR Electronically Filed ITR Form or Form ; Filing Reference Number. How to get a TIN (Taxpayer Identification Number) ID from the BIR in the Philippines? Here are requirements, forms, steps and procedures in. For new business owners, if you do not get your Tax Identification Number (TIN) via mail or SMS two weeks after you register your business at CAC.