A true Visa-on-Arrival as used normally is not accurate. This implies just rocking up on any flight to Myanmar and buying a visa on the spot, without advance arrangements--similar to buying a tourist visa in Laos or Cambodia. AFAIK, Myanmar has never allowed this though they did briefly have an e-visa service. The terminology you may be looking for is "pre-arranged visa" not true VOA. This is a visa that is pre-arranged through an agent or online methodology, then put in your passport when you arrive at the airport on the designated flight. That's what Myanmar discontinued a while back. And even then, I thought they limited it to citizens of countries where there was no Myanmar Embassy. However, I have heard that Myanmar has recently re-instated prearranged visas but I've not looked for corroborating details anywhere. I suggest you contact the airline directly and ask. If no definitive reply and assistance with prearrangement paperwork is forthcoming, do the safe thing and get a visa the old fashioned way, in advance at a Myanmar mission.
From the internet, here's something recent. Note that they use the VOA terminology, but it is in fact prearrangement and payment in advance. Read carefully for the overall processing time.