Why do I see certificates here if I haven't bought any?

The Certificates I manage section is designed for technical, administrative, or advisory profiles.

If you see certificates in this list, it means another platform user (your boss, a client, or a colleague) has invited you as a Manager of their account and assigned you the technical task of emitting these certificates on their behalf.

In the Delegated by column, you can see exactly who the original owner of the product is.