How do you show letters as strike through on an iphone or ipad?

How do you show letters as strike through on an iphone or ipad?

You can't without using a third party app to edit text.

Depending which version you are running there's/was an option in notes for struck-through but I only get black italic or underline.

Not with the keyboard or anything. I don't think so and like the other user said, you need some other app or program to do so. You can't simply strike through whenever you want to.