@William **********

Before your departure you will find or see a counter or the officer at the departure check-in counter will send you to that counter where you can pay the penalty easily...

You can extend your visa for 30 more days but people who are traveling from the countries like India, Pakistan, Bangladesh, Sri Lanka, Iran, Nepal, Togo, Nigeria, Uganda, etc. can extend only for 7 days. The price of the visa is 1,900 baht whether you extend it for 30 days or 7 days.

To your question- you can't extend more than 60 days unless you hold a special visa or have some health or other issues. The 90-day Special Tourist Visa (STV), which allows two 90-day visa extensions at the local immigration office. There are certain requirements needed for the STV, but it allows a visitor to stay in Thailand for up to 9 months.