Your home is exempt from all ad valorem taxes on its assessed homestead value if you are a veteran with a 100 percent service-connected disability rating, a veteran aged 90 or older, the surviving spouse of either, or the surviving spouse of a service member who died on active duty or on active duty for training in a reserve component.
Apply through the tax assessor office in the Mississippi county where the property is located, not through the state. Ask them to confirm the filing deadline for your county.
Your DD214, your VA rating letter if you are claiming on disability, proof of age if you are claiming at 90 or older, proof that you own the home and live in it, and a death certificate or casualty documentation and marriage certificate if you are a surviving spouse.