Make sure you download the precompiled utilities you need from the link below
https://developers.google.com/speed/webp/docs/precompiled
Extract the archive you download, and navigate to the ‘bin’ directory via your terminal/command line
Execute the command below in your terminal
cwebp -q 50 image-file-name.jpg -o image-file-name.webp
The ‘-q 50’ means you’re converting the image at a quality of 50%. If you want you can decide to convert at a quality of 100%, which would be ‘-q 100’.