Has my MacBook been compromised? If so, what should I do?

I have a rather antiquated MacBook, an 11 inch, early 2014 using Big Sur. I was making a purchase today and I saw an auto fill option popup asking me to update information. It generated a name and phone number I've never input.

I went into my browser's autofill and I saw this name and phone number.

I take it my MacBook has been compromised? What would be the best course of action?