Can I change my signup or referral link to show my company name instead of my personal name?

Your client-facing branding on the signup link is controlled by your Branding settings, so update your logo and company name there and clients will see your business identity when they land on the page, not your personal name. The underlying signup link stays connected to your account no matter what you display, so updating branding will not break the link or any tracking on it. Find your link under Businesses using the Share Sign Up Link button in the top right.