@Khas, Mohit , Apologies for the delay in responding from over the weekend.
The feature is shared by both products ( App Service and Azure Functions). It should work for App Service as well, please see this doc -This topic shows you how to work with secrets from Azure Key Vault in your App Service
or Azure Functions application without requiring any code changes.
Please let us know if this works/you're facing any specific issues (errors) implementing the same for App Service/ or if I have misunderstood your question.