DOES THE IPAD PRO SUPPORT A MOUSE AND IF SO WHICH ON

You can use a mouse if you enable Accessibility>Touch>Assistive Touch.

You can then pair a Bluetooth Mouse and an Apple Wireless Keyboard.

It is noted that the Apple Magic Mouse and Magic Trackpads are not supported.

There is no mouse support.

Try this: With the virtual keyboard up, place two fingers on the keyboard area. The board keycaps should appear to "blank out" and you can use those two fingers to move the insertion point to wherever you need it, just like that area is now a trackpad. Very handy.

The wireless Bluetooth mouse IS currently supported under Accessibility settings in the iOS Settings app.

Most third party wireless Bluetooth mice shoukd work with the iPad Pro.

It does take some doing to setup, though.

I would advise doing a YouTube video search for how to setup and use Bluetooth mice with iPadOS for the correct set up procedures.

Apple's own wireless mice and tracpads are NOT officially supported, as yet, but there is a work around procedure to get these to work.

You can find those procedures in a YouTube video search, as well.

The Apple wireless Bluetooth input devices that work are the 2nd gen Magic Mouse and Magic Trackpad.

The Apple input devices are NOT “officially” supported, but you CAN still get these to work under Accessibility settings under Switch Control.

Make sure under Switch Control, Mouse Keys is toggled/switched to OFF!