NemID is a popular authentication method in Denmark, which requires users to insert a unique key. Depending on how the plugin was set up, the log in page will be similar to the figure below.
NemID user can also use the NemID code app to authentication instead of using code card, read more in this article.
The plugin-in can also handle NemID with a local certificate file.
This article only explained the process of logging in. If you are interested in actually setting up this page, please go to NemId Authentication Connection