Venkat, did you select for CP in your 140 application. If selected fine otherwise
you have to file for I-824. The documents needed are
1. Birth certificates for all individuals in your GC application.
2. Marriage Certificate.
3. Pcc from your area Consulate General of India office, I think right time to apply PCC is after 140 approval because PCC in needed only for Interview.
You can get complete list of Doc\'s from SRIFX list.