In PowerPoint 2016, within the Customize Quick Access Toolbar drop-down menu, you will find the Touch/Mouse Mode option. This essentially is a toggle button that alternates between touch and mouse modes. Touch mode is the default mode when using PowerPoint on a touch device such as the Microsoft Surface or other tablets, and lets you use the program even without a mouse. And Mouse mode is the default mode for PowerPoint 2016 when working on a non-touch enabled desktop or laptop. The larger question though is why you can toggle to the Touch mode in a non-touch device. If you are using PowerPoint on a desktop, why you need the Touch mode?