If you find that the default file format for your iPhone photos is HEIC and you want JPG instead, you can change it like this.[UPDATE]
From Wikipedia: “The High Efficiency Image File Format (HEIF) is a container format for individual images and image series. HEIF image files are usually saved with the filename extensions #heif or #heic. ” [or #HEIC]. It was introduced by Apple in iOS 11.
Suggestion For You:
iOS 13.x has not changed the technology since I wrote my original article on April 3, 2019. As a reminder, I explained:
Windows 10 supports HEIF, but there is a lot of momentum on the JPG side. In the past two years, I have not seen any evidence of a radical and widespread change in HEIF / HEIC, except perhaps for some professional photographers. Finally, early 2019, Google Android pie began to provide support to HEIC.