Why Won't My HEIC Photos Open?
HEIC is Apple's format. Windows and many other programs need an add-on, or a conversion to JPG.
HEIC is the format iPhones use by default. Apple software reads it everywhere. Windows needs an extension from the Microsoft Store, and plenty of other programs, printers and photo services simply do not support it.
Converting to JPG solves it for good. JPG is understood by everything. The file is a little larger, and for a family archive that is a fair trade for being able to open it in twenty years.
Takeout JSON Metadata Fixer converts HEIC to JPG and carries the date, the location and the orientation across, so nothing is lost in the conversion. It runs on your own computer and is free for your first 500 photos.