Need to convert HEIC to Jpeg. You can easily change iPhone images to JPEG files on Mac or PC.
The first option on Mac is using the preview app and saving it as Jpeg.
Other option is using a free web tool that you can get here.
HEIC or HEIF are new higher efficiency formats for iPhone and iOS 11 or later. But sometimes, you still need a Jpeg file and you'll need to make that conversation.