Hello, @Phani Sri Siva Charan Kandukuri !
Which azure service can we use to run user code from a web application?
There are a variety of ways that you can accomplish this but it sounds like you may want to use Azure Functions at the core of your solution and perhaps Azure App Service to host your website although you could host a custom solution on an Azure VM. I'll add tags to make sure that this question gets additional visibility.
Azure Functions can help you build a coding web application like HackerRank or CodeChef by providing a serverless compute service that enables you to run code on-demand without having to explicitly provision or manage infrastructure. You can use Azure Functions to execute code snippets or scripts in response to events, such as HTTP requests. This would allow you to execute code written in multiple programming languages, including C#, Java, JavaScript, Python, and PowerShell and this can be integrated with other Azure services such as Azure Storage, Azure Event Hubs, and Azure Cosmos DB.
Azure App Service can be used to host a website by providing a fully managed platform for building, deploying, and scaling web apps. You can deploy your web application to Azure App Service from a source code repository, such as GitHub or Azure DevOps, or from a local Git repository. Azure App Service provides built-in support for continuous deployment, so you can automatically deploy updates to your web application whenever you push changes to your source code repository.
Does that sound like what you are looking for?