Are you using the Photo Extension? If you are using the Photo Extension on iOS, then unfortunately, Apple does not support the use of RAWs in Photo Extensions on iOS. I have asked Apple’s engineers about this year after year, but nothing has come of it. I suggest using Nitro on iPad as an app instead, which will get the RAW data. You can switch between RAW and JPEG in Nitro in Edit. There is a little button below the histogram that looks like an R on top of a box.