Screen saver is program that helps to show some specific message on screen when you are not working on your PC or It is widely used to save screen, the name itself tells us that screen saver.
Through screen saver you can show black blank screen, you can display patterns, images, texts and etc. It will pop-up when computer is not in use.
Screen-saver programs were designed to help avoid these effects by automatically changing the images on the screen during periods of user inactivity.
This is mostly used for power management, by displaying screen saver you can save your power.
To set screen saver on Windows 10 you have to follow these steps or you can watch video on YouTube, that is step by step guide to set screen saver on Windows 10.
Start>>Setting>>Personalize>>Lock Screen>>Screen Saver>>Now set screen saver that you want and set timer to display your screen saver, that's it.