After more than 15 years covering everything Apple, it’s with a heavy heart we announce that we will no longer be publishing new content on iMore and the iMore forums will be closing as of November 1st, 2024.
I believe this can be accomplished through Restrictions. I'm assuming you either don't have a phone that supports Siri or you have Siri disabled? Unfortunately, I can't verify this on my device as I have Siri and not Voice Control. I'd recommend creating an account here on the forums and providing us with a bit more information about what device you have and what you're trying to accomplish.