Turn off track pad when mouse is present

just running the by everyone. I'm configuring a dell inspiration 13 7368, I have been unable to turn off the trackpad. No options seem to be available in either control panel or setting/trackpad or settings/mouse. and no trackpad software. although the trackpad works great. I just need to turn it off to be able to type.
I've updated to 1809 xxxxxx.195. Has anyone else noticed the loss of this setting? or know where the setting moved too.
Not getting much help on the Dell forum. Using a Logitech MX 2 wireless

It may be more of a hardware thing that in the Operating System. All of my Notebooks have one of 2 hardware methods, one way is with a slide switch on one edge and the other is a combination of the Fn key + another Fx key that toggles it On or Off. Have seen where some versions of Windows can disable the Touchpad when a USB mouse is plugged in but not all machines seem to have that feature.

I forgot to also mention that some Notebooks can use only an Fx key to do it so experiment with Fn + Fx or the Fx only key, the symbol will look like a square with 2 smaller squares and the color may be the same as the Fn key marking.