Preferred method to verify businesses?

What's the best way to verify a business account to ensure the person creating the account is both affiliated and has the proper auth with their business to perform actions on your platform?

Is there a fully programmatic way? Like use lob or some service to send a physical postcard to the address they list? Phone verification code checked against a Google business listing's phone number? Requiring the account email to use the tld of the business website (although some bigger businesses use different, internal domain names than their customer-facing listing).

Any ideas or known best practices? Thanks!