For a 30 day extension you need to physically go to your local immigration office with your passport and a copy of a filed TM30 from your landlord or hotel.
it doesn’t matter what visa you hold, you automatically become a Thai tax resident by residing 180 days inside Thailand in a calendar year. There is no other qualifying criteria. As a Thai tax resident you are legally obligated to obtain a TIN within 60 days of receiving assessable income.