The delegates need to check the list of the countries that have the visa exemption agreement with Thailand. http://www.thaiembassy.com/thailand/changes-visa-exempt.php
Holders of normal passports of the 55 countries are granted visa-free travel to Thailand for a period of up to 30 days.
When applying for a tourist visa, certain documents and fees are needed to obtain one. The documents and the fee are subject to change anytime and without prior notice.
You can learn more information in Thailand Tourist Visa guide provided by Thailand Embassy . http://www.thaiembassy.com/thailand/thailand-tourist-visa.php