After watching a young relative type on an iPhone recently, I realized he didn't know how to use the "iPhone caps lock" feature. I assumed a person younger than me would know how to use the iPhone caps lock feature, lol, but it's not too surprising, because enabling the caps lock feature isn't the most obvious thing in the world.
iPhone caps lock
To use the iPhone caps lock feature, whenever you're typing something -- like composing an email -- just tap the iPhone Shift button twice. You need to do this quickly, similar to a double-click.