RAW and ProRAW photos captured on an iPhone use the industry standard digital negative (DNG) file format.
DNG is a lossless format equivalent to RAW. Originally DNG is an Adobe's proprietary image standard that was created to store image data in a generic, highly compatible format. DNG is the file used for all RAW photos on an iPhone.
You can open both type of files with the majority of the editing apps out there - like Lightroom, Darkroom, etc - which are compatible with DNG files.
You can share the original unedited RAW or ProRAW photo, which has the .DNG file extension. And if you edit the photo in the Photos app, you can also share the edited version, which has the .JPG file extension when shared.
More info on the official apple support: https://support.apple.com/en-sa/HT211965