How can I extend my tourist visa in Udon Thani and what documents do I need?

To extend your tourist visa in Udon Thani, you need to visit the local immigration office. Required documents typically include a copy of your passport data page, a copy of your arrival stamp, a passport-sized photo, a TM30 form (if applicable), and 1,900 baht in cash. It's also worth noting that there are upcoming closure days for the Songkran holiday on April 12, 15, and 16, so plan your visit accordingly.