When you apply for a PAN Card, you get a token number, also sometimes called an Acknowledgement Number, or a Coupon Number. Depends on where you apply and who issues you the acknowledgment receipt.
This “token number” or “Acknowledgement Number” or “Coupon Number” is the number that is used to track your PAN Card application status.
“Coupon Number” is generally a term used in the UTI related website, and acknowledgment issued by UTI Agents.
“Acknowledgment Number” is a term used in NSDL related websites, and acknowledgment issued by NSDL authorised agent offices.
The following link is helpful to check the status of your PAN Card Application, and also get the status as an SMS to your mobile.
Hope this helps.