Or, put another way, put a Mac into your iPad. Ron McElfresh explains VNC.
Think Virtual Network Computing, a floating standard that goes back decades, but basically allows one computer to connect to and control another computer. Your Mac has this built in already with Screen Sharing. A Mac on a local network can share the screen of another Mac. Under the right conditions, a VNC application can make that happen across the public internet.
And for the iPad and Mac combo?
Think Mac screen on iPad Pro. What’s missing is multi-touch control with your fingertip, but the Mac’s screen pointer works perfectly with your fingertip so you can control what’s on your Mac from the iPad’s screen (works great with iPad Pro, but very well on iPad
I tried it. Not bad.