How to screen record with audio?

I use an app called Screencast o Matic

it’s free although you will get a regular popup suggesting you pay to upgrade

it records with audio if you want it to.

By definition, a screen recording does not include audio. iOS/iPadOS does not provide the facility to simultaneously record audio along with a screen recording.

Apple do invite submission of feature requests via its Product Feedback portal:

Product Feedback - Apple