Screen recording on iPhone?

Hello! Lately I've taken an interest in doing more level 3 raids solo and even duoing level 4s with my wife. I'd really like to be able to record the raid battles, but from the limited research I've done it looks like this is not as easy on an iPhone as it is with Android. Is there a way to record your iPhone screen without streaming to another device? I've got a surface that I can use if all else fails, but I really don't want to have to carry it around for this.