Medical Provider Signature. Date. These certificates validate your medical need for darker window tinting, granting you legal permission to exceed the standard tint limits.In most cases, you will need to fill out a vehicle tint-waiver request form — or some form along those lines — depending on where you reside. How to fill out the Application for Window Tint Medical Exemption? You need a prescription written from your doctor and you submit it on the adot website that way you can Tint your windows as dark as you want.