How to work with shields.io badges?

Looking at shields.io website, I did not understand how to get a shields.io packagist version badge. How to generate it?

Not sure what a packagist version badge is, but to create a button, you enter your label and message, select the colour and click make badge in the section headed Your Badge. Assuming you want a static badge.

It’s not a well-designed website as it’s not immediately clear that’s a form.