Apple’s iPhone and iPad take photos in the HEIF image format, and these photos have the .HEIC file extension. Not all devices support this extension. Qiscus Multichannel itself don't support this type of file extension.
If a user send a .HEIC file, it will not be rendered as image but as a file attachment instead. You can download this file, and open it using iPhone or iPad. Or if you dont have those devices you can try to convert the image to a format that your device can open like .jpg, or .png using services such as https://heictojpg.com/