ASP.NET Core Basics - Accessing Configuration Settings From Multiple Sources

In older Asp.Net Version, we typically store the configuration settings in web.config and access it using ConfigurationManager Class. This worked well in the past however it is not good enough for modern technologies like hosting in cloud or container based solutions. Moreover, storing the sensitive data in web.config poses security risk if the file is check in to source control by accident.

source https://www.c-sharpcorner.com/article/asp-net-core-basics-accessing-configuration-settings-from-multiple-sources/