How do I control access to my camera on my iPhone 12.

Hello, Rob. On which iOS version are you right now on your iPhone? The feature called "App Library" might help maybe to prevent your kids from using the Camera app on your Home Screen. Also make sure to check out this link for more information.

Hope that helps.

Organize the Home Screen and App Library on your iPhone - Apple Support

Kind regards!

We have no way of knowing the reason you can’t remove the camera from the LOCK screen; it’s probably so if you have a photo op you don’t have to take the time to unlock the phone and find the camera icon. Photos taken when the phone is locked can be viewed from the camera app on the lock screen, but no other photos in your photo library can be viewed, thus preserving your privacy.

One solution to your problem is don’t leave the phone where two small kids have access to it. I’m sure there are many things in your home that are inaccessible to your kids; just make your iPhone one more such item. Or get them their own inexpensive camera so they can take as many photos as they want without cluttering up your phone.

RobPembroke wrote:

I need to remove access from the Home Screen, but be able to access the camera (or an alternative app) when the camera is unlocked.

That's not possible.