Asp.net Core has a web.config, but you use it in your migration you will be limited to only using IIS and not Linux Web Server like Nginx
Convert global.asax to startup.cs file
Migrate web.config file to appsettings.json if you want to utilize cross-platform aspect of .Net Core
Move all static files to a wwwroot folder (Remember to move only assets that you need, the files in folder might be compiled and sent to the front-end. Research about the difference from Asp.Net Website and Web Application: hit, websites only compile assets that are referenced in the master page, while web application compiles everything in the form of a dll)
Remove HttpContext references: this API is still undergoing major writes. - HttpContext.Current API is not even included in core 2.2
Update Authentication and Authorization API - If you are using Authentication API before Identity, you are advised to update now.
Add necessary Front-End library
Use BundleMinifier extension instead of System.Web.Optimization
Migrate all your Views -Razor is backward compatible -Conver Views/Web.config to Views/_ViewImports.cshtml -Convert namespaces.add to @using -Migrate any settings to main application configuration - @Script.Render and Style.Render do not exist anymore