lobsterghost1 wrote:
As long as the iPad and iPhone are on the same Apple Account and you have iCloud sync turned on both devices, you can certainly take a photo on your iPhone, then move over to your iPad and edit it as soon as it syncs there.
I believe that the OP wants to use the iPad's screen as a remote electronic viewfinder for composing the photos that the iPhone is going to take, before the iPhone takes them.
Google's "AI overview" suggests that the BlackMagic Camera app and the Capture One Mobile app can support such tethering, and that other apps like DTO and Accost can support live mirroring. The AI instructions typically involve installing the same app on both devices. In the case of the Capture One Mobile, the instructions said to install the app on the iPad, but said nothing about installing it on the iPhone.