Touch on login screen

The two most common queries regarding touch on the login screen is, will it work and can I use an on-screen keyboard.

For the three main desktop OS the answer is as follows:

OS Description 
 Windows  Yes Both UPDD mouse and HID touch interfaces work. With the mouse  interface touch on the login screen to show the password field. With the HID interface swipe up the screen to show the password field.
 MacOS  Yes Yes but with MacOS 10.14 and above you must manually give accessibility permission to Note: Touch does not work on the "special pre-boot' screen shown if you have FileVault enabled.
 Linux  Yes Yes, when using the UPDD uinput interface
 Windows  Yes Yes, if configured in Windows to do so
 MacOS  No Prior to 10.15 it was not possible. With 10.15 an on-screen keyboard can be configured.
 Linux  Possibly A number of articles are on the web to show how this can be achieved for various distributions