Ala. Code § 40-26-5

On or before 30 days after the end of the tax year, each person, firm or corporation liable for the payment of a privilege tax as levied by this chapter shall make a return showing the gross proceeds of business done and compute the amount of tax chargeable against him or it in accordance with the provisions of this chapter and deduct the amount of monthly payments as hereinbefore provided, if any have been made, and transmit with this report a remittance in the form required by this chapter covering the residue of the tax chargeable against him, to the office of the department, and such report shall be verified by oath.