1. Find the ID

of your touchpad with xinput list:

xinput list
⎡ Virtual core pointer                    	id=2	[master pointer  (3)]
⎜   ↳ Virtual core XTEST pointer              	id=4	[slave  pointer  (2)]
⎜   ↳ SYNA3296:00 06CB:CD50 Mouse             	id=9	[slave  pointer  (2)]
⎜   ↳ SYNA3296:00 06CB:CD50 Touchpad          	id=10	[slave  pointer  (2)]    <------
⎣ Virtual core keyboard                   	id=3	[master keyboard (2)]
    ↳ Virtual core XTEST keyboard             	id=5	[slave  keyboard (3)]
    ↳ Power Button                            	id=6	[slave  keyboard (3)]
    ↳ Video Bus                               	id=7	[slave  keyboard (3)]
    ↳ Power Button                            	id=8	[slave  keyboard (3)]
    ↳ AT Translated Set 2 keyboard            	id=11	[slave  keyboard (3)]
    ↳ Wireless hotkeys                        	id=12	[slave  keyboard (3)]
    ↳ HP WMI hotkeys                          	id=13	[slave  keyboard (3)]

Apparently, the one called „… TouchPad“ has id=10.

2. List the „props“ properties

with the ID list the props

xinput list-props 10
Device 'SYNA3296:00 06CB:CD50 Touchpad':
	Device Enabled (168):	1
	Coordinate Transformation Matrix (170):	1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
	libinput Tapping Enabled (326):	0      <------
	libinput Tapping Enabled Default (327):	0
	libinput Tapping Drag Enabled (328):	1

Our Property frp tapping is 326

3. Set Tapping to 1 to enable

Set the Tapping (326) to 1

xinput set-prop 10 326 1
                             ^

https://unix.stackexchange.com/questions/438725/disabling-middle-click-on-bottom-of-a-clickpad-touchpad

https://docs.xfce.org/xfce/xfce4-settings/mouse

https://wiki.ubuntuusers.de/Howto/Touchpad

xinput Artikel über Mauseinstellung – xinput – touchpad einstellen @ linux