Hi @Sundaramurthy, Hariprasad (Contractor) ,
Thank you for posting query in Microsoft Q&A Platform.
You mean "DocumentDB Account Contributor" role assignment to ADF Managed Identity?
I tried same. It works with out any issue. I am able to see my ADF managed identity under "DocumentDB Account Contributor". Please check below screenshot.
If above is not the case, then please share details of the steps to follow to repro your scenario. So that I can try same to help better. Thank you.