Yes, it mandatory to provide the Assessing Officer (AO) Code in Form 49A/49AA. AO Code (i.e. Area Code, AO Type, Range Code, and AO Number) of the Jurisdictional Assessing Officer must be filled up by the applicant. These details can be obtained from the Income Tax Office or PAN Centre or websites of PAN service providers on www.utiitsl.com or www.tin-nsdl.com