Disability retirement pay you receive for an injury or illness that resulted from active service is not counted as taxable income. This also covers VA disability compensation and pension payments, grants for a wheelchair accessible home, grants for a vehicle if you lost your sight or the use of a limb, and dependent care assistance benefits.
There is nothing to apply for. Leave these payments out of the income you report on your Alabama return.
Your VA award letter showing the payments and what they are for.