How do I control powerpoint or google slides from my iphone without installing any extensions or software on the computer?

I'm open to downloading any apps on my iphone and it is not jailbroken

If there's an app to make your phone usable as a wireless mouse for the computer, that would do it.
a single left-click is all it takes to advance slides.
kind of impossible to do without software on the computer. If anyone could control any computer from their phone without authorization, can you imagine what kind of security problem that would be?
of course you could always just use a small wireless mouse with a USB dongle to accomplish the same thing…

You throw your phone to hit the arrows on your computer's keyboard?

Not happening, iPhone or iPad is an Apple product, not Microsoft, and Apple would not have a Microsoft functionality on it as a stock tool, some may view that as egotistic or monopolistic but this is a clear-cut commercial decision. Especially if Jobs had any say about that.

Same goes with Google, even clearer if anything. But making it like a mouse is just, "don't rock the boat" way.