Here’s how I set things up to automatically disable the touchpad while typing in my laptop, using the driver’s automatic palm detection. These are just my notes. Check the entire Arch Wiki entry on Touchpad Synaptics. First of all you should test if it works properly for your touchpad and if the settings are accurate. Enable palm detection with synclient PalmDetect=1. Then test the typing. You can tweak the detection by setting the minimum width for the touch to be considered a palm, for example synclient PalmMinWidth=8.