Can you change the iOS on an iPhone first generation? Can you change it at all?

What do I have to do to be able to download an app that says it requires iOS 6 when I have iOS 3.4

My guess it that hardware is probably too oudated to run the later OS's.

You can't get ios 6 on the 1st gen iphone/
ios 3 is the last firmware it will get.
if you need a newer iphone, email me i have a few for sale or trade.