Download and install HEIC Converter on your computer, then launch it. Connect your device to this computer if you want to convert pictures are stored on your devices.
Click the Add HEIC button to open HEIC files or folders on computer, and then click Open. If you want to convert HEIC files from iPhone/iPad/iPod touch directly, go to This PC\Device Name\Internal Storage\DCIM.
Check the HEIC photos which you want to convert from the list, and you are allowed to select the conversion format, quality, keep edit data or not and output path here. And then click Convert under the options.