Ala. Code § 40-21-16

The Department of Revenue of Alabama shall receive all such statements offered to it under the provisions of this chapter, shall endorse upon each the date upon which it was received and sign the endorsement officially. It shall examine the statements as soon as may be practicable; and, if any of them are found to be insufficient or if said department shall believe other or further information to be necessary, it shall at once demand such additional statements and information as it may think proper.