HTTPTriggerFunction.cs

 /// <summary>
        /// Use Attribute which will help to check token
        /// </summary>
        /// <param name="req"></param>
        /// <param name="log"></param>
        /// <returns></returns>
        [FunctionName(nameof(HttpTriggerFunction.TestAuthorization))]
        public IActionResult TestAuthorization(
            [HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = null)] HttpRequest req,
            ILogger log,
            [JWTAuthorization()] JWTClaim jwtClaim) {
            log.LogInformation("C# HTTP trigger function processed a request.");

            // Check token is valid or not
            if (jwtClaim == null)
            {
                return new UnauthorizedObjectResult("Invalid token");
            }

            return new OkObjectResult("Valid Token");
        }