If you arrived in Thailand using a 60 Day Tourist Visa, or a 30 Day Visa Exemption then you are allowed to obtain one 30 day visa extension.
But due to Covid-19 you also can obtain a 60 Day Covid Visa Extension (multiple times).
If you are 50 years, or older you may qualify for a NON-O / Yearly Extension of Stay based on Retirement.
For those who are younger than 50 years of age, and wish to stay in Thailand long term it may be useful to first contact a Visa Agent to determine all of our options.
In order to extend your visa by one year you must first have a non-immigrant visa type, and qualify for the yearly extension of stay. There are many visa categories which allow you to extend your stay yearly, and because of this it may be helpful to first consult with a Visa Agent to quickly determine your best option.
You can message Thai Visa Centre over their 24/7 @LINE Support Account.