Use an online HEIC to JPG converter
Open the HEIC file in a photo app and export or save as JPG
On Mac, open the file in Preview, then choose File > Export and select JPG
On iPhone, transfer the photo to a computer and convert it there
On Windows, install a HEIC codec or use a converter app
Use an image editor like Photoshop, GIMP, or Paint.NET to open and save as JPG
Use a batch conversion tool if you have multiple HEIC files
Rename the file extension only if the image is already in JPG format, not for conversion