A Web Config file is the main settings and configuration file for use with ASP.NET. This article will show you how to create your file and where to place it in your 123-reg Hosting package.
Create a txt document with your Web.config settings.
Below is an example that shows a minimal Web.config file
<?xml version="1.0" encoding="utf-8" ?>
Save the txt file as Web.config.txt.
Upload the file to the root directory (web/content/) of your windows hosting package.
Rename your Web.config.txt file to Web.config by removing the .txt extension." This can be done using your FTP client
You have now added your Web.config file.