要低评论，所以我会发布作为答案，请按照此 答案.

对我来说，我只是右键单击项目，选择 Add ->新建 Scaffold Item，在左侧窗格中的新对话框中选择 Identity，然后按照提示进行操作.

login.cshtml 页面是在 Areas/Identity/Pages/Account 目录中创建的.

I'm trying to implement OAuth2.0 for my web application. I have done that following this link.

I have registered with 2 external providers Microsoft and Google. I have added Authentication in startup.cs file as well.

So when I run the application, click on Login button on top right corner, a Login page is displayed.The URL it is showing is https://localhost:44325/Identity/Account/Login.

But I'm unable to find this page anywhere in my solution. I want to modify this page's design and want to make this my first page as soon as I open the application.

How do I do it?

Edit

To low to comment so I'll post as an answer, follow the instructions at this answer.

For me I just right-clicked on the project, selected Add -> New Scaffold Item, picked Identity on the new dialog, in the left pane, and followed the prompts.

The login.cshtml pages were created in the Areas/Identity/Pages/Account directory.