In terms of phones to use, below are the specs needed, but any Android or iOS phone from the last 5 years should be fine.
A smartphone model with:
A camera with a minimum of 12 megapixels.
An operating system of at least Android version 6.0 (API 23) and above
All iOS phones from version 11 and above, including iPhone 5 and newer, work flawlessly.
We use a number of different models for testing, including recent iPhones, Google phones, and Samsungs.