HEIF/HEIC are Apple's newest image format, which takes up less space while ensuring high image quality. It only available on Apple devices with latest versions of iOS (11) and latest version of MacOS. Unfortunately, for some, older macOS versions or iOS or Windows are not supported.
FonePaw HEIC Converter is an offline file converter that can make this format recognized on Windows and viewed on any device. The process is easy; simply add the .heic files and then select output path and ideal format. Voila! you can view those HEIF photos as .jpg/.png on Windows or Android phones. It's that simple.
Overall, FonePaw HEIC Converter Free does the job quite well, although the interface is very dated, the conversion process is easy to learn, and anyone with basic skills will be able to use this app to convert their newly iOS/MacOS formatted files and view them on any supported device.