Can you please let me know if the configuration from 2 Node RAC ( Primary database for EBS r12 ) to Physical standby
Yes, you may convert your RAC DB to Non-RAC DB in a secondary site, and you may achieve this using Rapid Clone. Please refer note:
Cloning Oracle E-Business Suite Release 12 RAC-Enabled Systems with Rapid Clone (Doc ID 559518.1)
Section: Section 6: RAC to Single Instance Cloning
Also i have installed grid sw and tried to run ASMCA and was not able to create the diskgroups. The grid is not running and we dont require it as we will not configuring RAC.
So should i run dbca from oracle home and create an ASM instance.
Correct. And in top of that you may use the rapid clone technology to place the Datafiles in the Standby site.
Please also refer note:
Question on Active Data Guard Reporting With EBS R12.1 (Doc ID 1451500.1)
MAA Roadmap for the E-Business Suite (Doc ID 403347.1)