To my fake name (from family and friends), anything official goes to the mailbox at my real address to which I have access to. But that rarely happens thanks to e-government. Because of presumed delivery, there's no benefit in receiving that kind of mail on paper, so I opted-in.

For e-mail, I use a domain with a catch-all mailbox. I rot13 the service name or whatever in the local-part to identify where the e-mail got leaked/sold from, which I feel like happens more often than not when buying anything from small e-shops.