What’s the difference between a visa and a status?

A visa is the sticker/stamp you receive through a U.S. embassy outside the United States. Status refers to the standing or position that the visa represents.
H-1B is often referred to as a “work visa,” but if you obtained H-1B status through a change of status within the U.S. (rather than a visa stamp), it’s referred to as H-1B status (work status). A changed status is recognized through a paper document issued by USCIS reflecting your standing. For example, when applying for a driver’s license at the DMV (MVC), since there’s no visa sticker in your passport reflecting your new status, you would instead bring the document proving that status.

It would be convenient to have an ID card matching your exact status, but in practice a driver’s license serves as your ID, while a paper document serves as proof of your immigration status — this blurs the line between “visa” and “status” for most people, so H-1B status is often casually referred to as a work visa as well.

Whether you call it a visa or a status doesn’t really matter. Unless you’re a professional in the field, there’s no real need to understand and carefully distinguish between the two.