An Administrator for a business is typically an owner, officer, member, partner, trustee, receiver or authorized representative for a business. To register as an Administrator, you must be identified on the business tax registration with the Department and provide your First and Last Name, Social Security Number, Date of Birth, Phone Number and E-mail Address. To be authorized on a business, you will need the Business’s Missouri Tax Identification Number, Business PIN number, and Federal Identification Number, if applicable. To add an authorized representative to your business account, complete and E-mail a Form 126 Registration or Exemption Change Request to mytaxmissouri@dor.mo.gov for processing.