The photo browser of Transcend's "for iOS" applications, such as the JetDrive Go app or the SmartReader, does support this file type, but if you would like to move or drag the HEIF/HEVC files to the Camera Roll, the file type needs to be supported by you iOS device as well.
If you drag an HEIF/HEVC format file to an iOS device that doesn’t support these file types, you may not be able to browse or watch the photo or the video.
If you would like to save images or videos in the most compatible format possible, go to Settings on your iOS device, and set the format to “Most Compatible”.
Path: Settings → Camera → Formats → Most Compatible
※ To learn more about HEIF/HEVC, please refer to the following link. https://us.transcend-info.com/Support/FAQ-1130