Hello @Shivam Saxena In case of App Services C:\ drive is for app-specific temporary local storage and that storage isn't intended to be used directly by the application code. Please refer to the official documentation :
https://learn.microsoft.com/en-us/azure/app-service/operating-system-functionality#types-of-file-access-granted-to-an-app
https://learn.microsoft.com/en-us/azure/app-service/operating-system-functionality#local-drives
Does this help?