You’ll need to tap the keyboard button at the bottom of the touch input keyboard to select the default touch keyboard if you want to use it. Once you switch to the handwriting input panel, it will automatically appear whenever you tap or click the keyboard icon on your taskbar. Touch the title bar of the panel with your stylus or finger to drag it around your screen and position it wherever you want it. To shrink it, tap the “Undock” button to the left of the “x” on the top right corner of the panel.
By default, it spans the entire width of your display. Tap the handwriting keyboard icon, which looks like a pen over an empty panel.