I'm aware of the Thailand eVisa website and have set up a profile there. However, I just want to confirm that it is also possible to apply IN PERSON at an immigration office while in Thailand. Is that correct? (visa type: Non Immigrant O)
TLDR : Answer Summary
Yes, you can apply for a Non Immigrant O visa in person at an immigration office in Thailand. Many immigration offices allow conversions to a Non Immigrant O visa while you are in the country, although most immigration interactions are typically handled in person.