Whilst I think this is a useful addition, I – like many – are probably wondering why it took Google so long to release it.
Google have published guidelines on how to add or edit attributes.
Simply head to your GMB dashboard, click on Info on the left hand menu and scroll down to the Attributes section which has the Tag icon, just above the business description, and click on the pencil icon.
From here scroll down until you see the Heath & safety section which will include options like ‘Mask required’, as per the screenshot below.
If you don’t see these options, then Google haven’t included your business category for this feature.
Once added, these attributes certainly aren’t as prominent as others. The Knowledge Panel screenshots below show the position of a Service Option attribute on the default Overview page, compared with the Health & Safety attribute on the About tab, accessible when you click on the > on the Overview page.