In the latest Windows 10, the touch keyboard can be activated by right click over the taskbar and select Show Touch Keyboard button option.
While there are also a few other things which we need to care about. For the touchscreen to work properly, you must have the latest touch hardware drivers installed. The later editions of Windows 8.1 and Windows 10, after it also comes with touch plus some additional or extended features.
Windows 8 was the first desktop operating system to introduce touch capability.