For linking purpose the user can either send an SMS to 567678 or 56161. It is desirable that name on both documents should appear in the same to the same otherwise it may not be linking. To link through the messaging system just type UIDPAN followed by your 12-digit Aadhaar number and after space type the 10-digit PAN number. And press send button to send it to 567678 or 56161.
e.g. UIDPAN 1235456781639 DWWP1536AN
While messaging make sure you are using the same Aadhaar registered mobile number. If you use any other mobile number then it will not work. If the linking is the successful user will be notified by SMS.
How To Link Aadhaar Card With PAN Card using Income Tax Department Website.
After verifying detail and your UID and click on 'Link Aadhaar Button'. You will receive an OTP to authentication purpose enter the same and you are done.