AuthenticationPage is something which you can add to your Application before letting the user to acces it. They can be usefull to see identicfcation the person who's is viewing the application After the Authentication procedure.
Authentication is a term that refers to the process of proving that some fact or some document is genuine. In computer science, this term is typically associated with proving a user's identity.
You can use this template and make changes for your own application I'm a learner and i build this on my own and some help of youtube for my future projects which i want to make authenticatable for identifying purpose.