On mobile you can get touch location from InputTouch event node.
So I can get the mouse position when testing on computer :
The real problem is when I test on mobile, the widget spawn at non-logic locations, often several in a row at the same place, and it change after 4,5,…,20 click.
InputTouch, drag a wire off of Finger Index, attach that to a Hit Results Under Finger By Channel, set the Target to Player Controller, from Hit Results Under Finger by Channel, pull a wire off of the hit result, attach that to a Break Hit, and pull a wire off of location to have your touch location.
In the included picture you can see how I have it set up, I also have a lot of other things going on, but the touch location part you are looking for can clearly be seen. Good luck!