Unable to set default values for SynPS/2 Synaptic
You can change the default value in your libinput config file located at
/usr/share/X11/xorg.conf.d/40-libinput.conf
(mine is actually 90-libinput.conf. anyways, something like this.)
Just add
Option "Tapping" "True"
For me, the complete entry is:
Section "InputClass"
Identifier "libinput touchpad catchall"
MatchIsTouchpad "on"
MatchDevicePath "/dev/input/event*"
Driver "libinput"
Option "Tapping" "True"
EndSection
See more at:
https://wiki.archlinux.org/index.php/Libinput
https://www.mankier.com/4/libinput