Another way of achieving this would be to use Widget Windows, and Simple Dialer Widget, both can be found on the play store.
Widget Windows allows you to create a floating window of any widget you have installed, you can customize size and transparency.
Simple Dialer Widget is just that, a dialer widget that is minimal in design and offers dial pad, call log, and contacts tabs.
Floating widgets created through Widget Windows can be minimized to an icon that can be freely moved anywhere on your screen. Tapping the icon will re expand the widget.
You can use another program called Custom Notifications to pin a shortcut of the Simple Dialer floating widget to your notification panel for easy access.
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