Permanent Account Number (PAN) is a 10-digit number issued by the Income Tax department on a laminated card to identify taxpayers. Obtaining more than one PAN is illegal. PAN remains permanent and does not change, but address changes must be updated. Application for PAN can be made through Form 49A at IT PAN Service Centers or TIN Facilitation Centers along with valid identity and address proof, payment of fees, and other required details.