In Unreal Engine, you may want to show a page to users for things like scoreboards, payments, or just to show a webpage. Unreal Engine 4 has a built-in plugin that you can enable that lets you do this. It does not work if your package for HTML5, and I have had some problems with IOS, even though it said that it would work there.
The first thing that you need to do is go to edit then plugins and search for web browser. Enable that plugin, and restart the engine. Once you do that, open your project, and create a widget by right-clicking on the content area and select UI and widget. Open the widget, and in the top left, under experimental, select web browser. Drag that onto your widget, and size it the way that you want. You can set the URL that it shows you on the right-hand side, once you have it in your widget, and it is selected. It works if you do not put https, and it also works if you do put https in front of the URL. For example, you could do https://google.com or google.com.
Once you have all of this done, close that window, and in the main editor, go to your level blueprint (you can find this under blueprints in the top middle of the main editor), and from the event begin play node, pick create widget, and pick your widget, then do add to viewport, and drag the return value of the first block (your widget) to the second (the add to viewport block). Now, the website you picked should show when you start the game. You can get the web browser off your screen with the get all widgets of class node, then the remove from parent node. You can put this on any event you want, for example when I press the spacebar, hide the browser or website.
I hope this helps you, I am glad that they have such an easy way to do this in Unreal Engine. If you are unable to get this to work, take a look at the video above. It also shows you a different way to have it set up, where you can have a button that removes the webpage from your screen.