Use a device or app that supports HEIC natively
On iPhone or iPad, open it in the Photos app
On Mac, open it in Preview or Photos
On Windows, install the HEIF Image Extensions from Microsoft Store
Use a compatible image viewer or editor
Convert the HEIC file to JPG or PNG
Upload it to an online HEIC viewer or converter
Open it in Google Photos or another cloud service that supports HEIC
Use Adobe Lightroom, Photoshop, or similar software with HEIC support