如何在应用程序投入生产时使用外部文件修改变量？

I have a web page made with .Net Core 2.1 and Vue, when the web application is in production mode, how to leave a config file as the Net Core appsettings.json and modify a variable. My doubt is also about how to build the content of it, and how to access to that variable in one of my component page in vue.I have a web page made with .Net Core 2.1 and V