@Kannusamy, Thaniyarasu 1) Azure Application Gateway is a web traffic load balancer that enables you to manage traffic to your web applications. Based on the source IP address and port, traditional load balancers route traffic to a destination IP address and port. Application Gateway gives you a finer level of control where traffic can be routed based on the URL. For example, you could define that if images is URL's path, traffic is routed to a specific set of servers (known as a pool) configured for images. You can read more about it here
2)This and this article might help you better understand the storage option.
3)Azure App Service enables you to build and host web apps, mobile back ends, and RESTful APIs in the programming language of your choice without managing infrastructure. It offers auto-scaling and high availability, supports both Windows and Linux, and enables automated deployments from GitHub, Azure DevOps, or any Git repo. More here.
Azure Container Instances is a solution for any scenario that can operate in isolated containers, without orchestration. Run event-driven applications, quickly deploy from your container development pipelines, and run data processing and build jobs. More info here
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