To pay with a major credit card, you must have your 12 digit tax account number and your credit card number. The Bexar County Tax Office offers the option of paying your Property Taxes online with either a major credit card or an electronic check (ACH).For questions, call the Bexar County Tax Assessor-Collector's Office at 210-335-6628. Obtain the invoice and customer number from the ROW administrative personnel.