For further info: https://www.freecodecamp.org/news/how-to-deploy-your-super-cool-node-app-to-azure-from-github-47ebff6c5448/
You must have a package.json with npm start script inside of it, a web.config which is saying iis, that this is a node application and last but not least the server.js file, which is the entry point for your node app.
In the second step, upload your node app to a repository on GitHub or a similar webservice.
Go into Azure portal and deploy your app from your GitHub repository in the deployment center.
If you have to compile your app from a script like npm run compile to build all assets and codes for productive mode, go to console in azure portal and run your build command.
Go to the application settings and add the variable WEBSITE_NODE_DEFAULT_VERSION with value 8.9.4. Ready! 🚀
You can use this boilerplate (including Express.js, Marko.js & Webpack) on Azure, simply follow the rules above! :D