Disability retirement pay you receive as a pension, annuity or similar allowance for an injury or sickness resulting from active service is not counted in your taxable income. The same treatment covers VA disability compensation and pension payments made to veterans or their families, grants for a home designed for wheelchair living, grants for a vehicle if you lost your sight or the use of a limb, and benefits under a dependent-care assistance program.
There is nothing to apply for. Leave these payments out of the income you report on your Kentucky return.
Your VA award letter or retirement paperwork showing the payments and what they are for.