You need evidence from the bank (it's a specific template they have) which shows your money were transferred from abroad.
Visa on arrival, see wikipedia, is a visa granted to some nationalities.
Most Europeans don't need visa at all, they just enter. They are exempt from visa.
Imagine a visa being a sticker that gets applied to your passport.
VOA subject citizens, when they arrive, they go to buy the sticker at the VOA counter, then they queue at immigration and get their entry stamp.
You don't need the sticker, you just queue at immigration snd get 45 days entry stamp.
In Chonburi if you apply for retirement visa you also need copy of id card of owner of your condo and signed copy of the house book (called tabien baan).