In Oklahoma, you will need a non commercial breeders license or commercial breeders license to own them OR whatever your state’s requirements are if you're near the border (ie. Arkansas)
You can contact your local game warden and schedule an inspection of where the ducks are going to be housed (form is on the site) before you purchase ducks. You then take the game warden's approval form and upload it to the application you submit online. I believe the cost for application and renewal is $10 per year. You must show a valid non-commercial or commercial license.