name on marriage certificate

Dear experts, my friend got married in 2012. But his marriage is not Registered yet. Using a notarized affidavit, his wife already has married surname in her pan card and bank accounts and even in their kids Birth certificate. They want to register their marriage now under Hindu marriage act and want to change the name of wife in all other documents including aadhar and passport using this marriage certificate. 1. Which name of his wife should be there on the marriage certificate: Maiden or married. I see both approaches in practice. 2. What process needs to be followed to use married surname for wife in the marriage certificate?? A joint marriage affidavit with name change clause suffices?? 3. Can his wife have her maiden name on the marriage certificate and still use it to change her surname in aadhar and passport to married surname?? 4. Which of the above two approaches is better if wife wishes to adopt husbands surname in all her documents like aadhar and passport??