Thanks for your reply.
But still I am getting same issue. I can able to invoke EBS navigation page from istore without any issue using following URL.
but same thing I cant do for quote letter function
I am facing insufficient privileges issue.
Usually we can download the quote letter from following navigation
Goto Quoting Sales Manager --> Quoting
-Query the quote that which is created in iStore using Quote Number.
-Change the Quote Status from Draft to Review.
-Approve the quote.
-Goto Action and select Print Quote.
-Then click continue.
-OAF Page will open there select the "Output Format" as pdf and click submit.
-Now we can see the Quote letter pdf downloading.
Could you please help me on this.