The difference is that one is for business and the other is for tourism. In both cases, please contact the embassy in your country and apply. Easy it ain't.
Try to pick a hotel that doesn't want the full amount up front. My partner was set to book a hotel that wanted 5000 THB deposit and the balance paid on arrival (the airline cancelled 1 day before we were going to pay the deposit!). We were also told that in the event of cancellation, the deposit could be moved forward.