How to get a command to run for all *.webp files in folder?

I want to convert some .webp image files to .png or preferably .jpeg

These commands both work OK:

dwebp file.webp -o file.png

ffmpeg -i file.webp file.png

How do I get them to convert every .webp file in the folder, not just file.webp?

So I would like them to change for example alpha.webp to alpha.png, even if I have not specified the name alpha.

The command lines above have been copied from https://winaero.com/convert-webp-png-linux/

The version of Image Magick I have is too old to be able to convert .webp files. I use Linux Mint Cinnamon 17.3 Rosa.

Thanks.