Do I need to apply for a visa or can I get 30 days and extend while in Thailand?

The user plans to arrive in Thailand on June 23 and return on August 4. They are inquiring about the need for a visa, specifically whether they can enter for 30 days and extend their stay at an immigration center. Comments clarify that eligibility for a visa-exempt entry depends on the user's passport, and that currently, holders of Belgian passports can obtain a 60-day visa exemption upon arrival, allowing them to extend their stay later if needed.