How long does it take to receive the approval email for a visa application from the USA?

@Jim *******

Well, giving up on the long stay OA Visa because we can't get Emirates to sign the overseas insurance certificate. They said they're not allowed to. I've contacted three different emirates/aig offices, one in thailand, one in malaysia, and one in England. No success. So going to try to get a tourist visa, and then get an agent once over there to switch over to a retirement Visa. Not sure which tourist visa yet, trying to figure out which one might be the quickest..... I think there's a 45-day Visa and 90 day Visa?