During registration of PMSSS 2021-22 while filling 12th roll no. the code which they are asking is for JK Board students not for CBSE. It will be a six-digit code present at bottom of the mark sheet. The format of the code will be something like 21AJTR.
If you are a bi-annual student or last year pass out, check the code only on your 12th new mark sheet, which will be formatted as 20AJTR(seven-digit roll no.)