Both of them are applied for outside of Thailand but immigration in Thailand can convert another type of visa into non-Imm O visa but not into a non-Imm OA.
The applicant of non-Imm OA visa must apart from the usual document for a non-Imm O provide a clean crime record and proof of medical insurance.
The non-Imm OA visa is a 1 year visa, so no need for doing a border bounce every 90 days, no need for 90-day address reporting as was the case for those having a multiple entry (multiple 90 days) non-Imm O visa in the past when that was available. Today you can only get a single-entry non-Imm O visa but the permit to stay based on it can be extended for a year at a time.