ASP Net Core Identity tutorial shows you how to ASP.NET Identity works in ASP.NET Core MVC by Building a User Registration & Login Page.
Introduction to Identity on ASP.NET Core • • 10 minutes to read • Contributors • • • • • • In this article By ASP.NET Core Identity is a membership system that adds login functionality to ASP.NET Core apps. Users can create an account with the login information stored in Identity or they can use an external login provider. Supported external login providers include. Identity can be configured using a SQL Server database to store user names, passwords, and profile data. 
Alternatively, another persistent store can be used, for example, Azure Table Storage. In this topic, you learn how to use Identity to register, log in, and log out a user. For more detailed instructions about creating apps that use Identity, see the Next Steps section at the end of this article.
Create a Web app with authentication Create an ASP.NET Core Web Application project with Individual User Accounts. • • • Select File > New > Project. • Select ASP.NET Core Web Application.
Name the project WebApp1 to have the same namespace as the project download. • Select an ASP.NET Core Web Application for ASP.NET Core 2.1, then select Change Authentication. • Select Individual User Accounts and click OK. Dotnet new webapp --auth Individual -o WebApp1 The generated project provides as a. Test Register and Login Run the app and register a user. Depending on your screen size, you might need to select the navigation toggle button to see the Register and Login links.
View the Identity database. • • Add the Register, Login, and LogOut files. If you created the project with name WebApp1, run the following commands. Otherwise, use the correct namespace for the ApplicationDbContext: dotnet aspnet-codegenerator identity -dc WebApp1.Data.ApplicationDbContext --files 'Account.Register;Account.Login;Account.Logout' PowerShell uses semicolon as a command separator. When using PowerShell, escape the semicolons in the file list or put the file list in double quotes, as the preceding example shows. Examine Register.
Creating a ASP.NET Core 2.1 project with identity configured you might miss controllers and many views that all have been available with ASP.NET Core 2.0 projects. All this functionality has been put into a Razor Class Library – a new feature with ASP.NET Core 2.1. You don’t have to deal with this code in your application. Not having the code you might ask how to customize the views.
There’s an easy way to do this as shown here. Identity with ASP.NET Core 2.0 Creating a new ASP.NET Core 2.0 project, using the project template with Visual Studio 2017, you can change the authentication to store accounts locally.