You don’t have to freeze the meat, but I highly recommend it. Wild game like deer often carries trichinella parasites, which can make you very sick. You can kill the parasites by freezing the meat for at least 30 days.
The marinade adds flavor and tenderizes the meat by breaking down its muscle fiber. Since venison is so tough already, this is a vital step—jerky that hasn’t been marinated for long enough feels and tastes like the sole of an old shoe.