Through eREG.

The eREGISTRATION (eREG) system is a web application system for various taxpayer registration services, such as TIN issuance, payment of registration fee and issuance of Certificate of Registration
The eTIN is a module of the eREG System. It offers convenient access to application for Taxpayer Identification Number (TIN) over the internet. It currently caters to the following types of individual taxpayers: Self-employed individuals such as Single Proprietors and Professionals, Mixed Income Earners (e.g. employee and single proprietor and/or professional at the same time), Employees, and Executive Order (E.O.) No. 98.
Single Proprietors and Professionals may apply for TIN straight to the eTIN. Each user should have a unique and valid email address through which the TIN and other instructions on taxpayer registration shall be sent. After securing the TIN, Single proprietors and Professionals are required to pay the Registration Fee (RF) of P500.00 thru Authorized Agent Banks (AABs) located within the RDO indicated on the email notification or thru the following BIR-accredited payment facilities:
- eFPS
- G-Cash
Employees may secure their TINs from their respective employers who in turn must be enrolled in the eTIN. Employers should be active Withholding Tax Agents for Compensation Earners. Employers may enroll in the eREG by clicking on Create Employer User Account at the left side of the page.
Prospective EO 98 taxpayers may secure their TINs through authorized Government Agencies and Instrumentalities (GAIs). GAI authorized users may logon to the eTIN by clicking on the Authorized User Login at the left side of the screen.
Securing more than one TIN is criminally punishable pursuant to the provisions of the National Internal Revenue Code of 1997, as amended. Every person who uses this facility for any purpose other than as intended will be investigated and dealt with accordingly.
NOTE: Issuance of TIN is free of charge.
For more information please visit: http://www.bir.gov.ph/