Ala. Code § 40-1-29

Whenever and wherever a notice is required by law to be given by the Department of Revenue, the Board of Equalization, the tax assessor or the collector relating to the assessment and collection of taxes, and the method of giving such notice is not prescribed, then such notice shall be given by either first class U.S. mail, or, at the option of the department, certified or registered mail, return receipt demanded, addressed to the last known address of the taxpayer.