The Assessor's duty is to locate, identify and equitably assess all property in Maricopa County. The goal of the Arizona Department of Revenue (ADOR) is to help business owners maintain tax and licensing compliance.Tutorial and step-by-step instructions can be found here. YEAR, E-FILE AND E-PAY THRESHOLD. Certificate is to document and establish a basis for state and city tax deductions or exemptions. The Assessor's Office maintains the ownership information for each parcel and updates the records when property is sold, transferred, combined or split. You might need to complete a transaction privilege tax application with the Arizona Department of Revenue. As of the 2023 tax year, Arizona has a flat income tax rate of 2.5 percent.