Activating Tablet Mode enables you to use Start screen instead of Start Menu and gives you the touch friendly experiences. Specially for those touch screen laptops this option comes handy, even for desktops if you wish to use a full screen Start Screen you can try this option.
To enable this option you need to first click on Windows icon to open Start Menu.
Then Click on Settings and inside Settings you need to select System.
Inside System you will see a list of options in the left bar where you will find the Tablet Mode option.
When you click on Tablet Mode you will see the option Make Windows more touch-friendly when using your device as a tablet. Toggle this option to enable Tablet mode on Windows 10