MS Windows does not have a keyboard shortcut for copy pasting text only. In the long run it can be very tedious copy-pasting process when creating presentations or writing documents.
Ditto (open source) is a good alternative for this. It is a clipboard manager, but in the simple form, it can be used for creating a global shortcut like ctrl-g and use it for pasting unformatted text. This is configured in the Ditto options tab “Keyboard Shortcuts”, see “text only paste”.