What's the difference between Invite and Direct in Referral Visibility?

The main differences are that if you choose Invite option, you can invite multiple people who then have the option to apply to work with you on the referral. You can then select any single colleague who applies. Note that they can negotiate with you over the referral commission that you will be paid.

If you choose Direct, you can select only a single colleague. This person then has the option to either accept or reject the referral, and cannot negotiate over the commission.