If you’ve transferred photos from your phone to your Windows computer and suddenly see .HEIC files you can’t open, you’re not alone. This happens because:
The link below from Microsoft explains this in more detail and includes troubleshooting steps:
Upload HEIF and HEVC photos and videos to OneDrive - Microsoft Support
This lets you keep using your phone’s default settings, and Windows will be able to open HEIC photos normally. These extensions cost a small amount.
HEIF Image Extension
HEVC Video Extension (may or may not be needed depending on your device; this is for viewing video files)
Once installed, your computer should open HEIC images without any issues.
You can switch your iPhone or Android device to use the Most Compatible format (JPEG).
This avoids HEIC files entirely but uses more storage on your phone.
Instructions are included in the Microsoft support article linked above for iOS devices. Android devices are all a bit different, but the process is roughly the same as on the iphone.