You can use the renewal option in the customer area to specify whether a domain should expire or be deleted at the end of the term.
Expire:
When a domain expires, it is returned to the registry and is not deleted immediately. What then happens to the domain is regulated by the registration conditions of the respective registry. Some delete the domain, others offer the option of reactivation. It is also possible that the registry takes over the domain in its own administration and bills it to the owner, since no deletion request was made.
Due to the large number of different endings, we cannot give you any general information. Therefore, if you explicitly no longer want a domain or have a deletion request, you should delete it.
Alternatively, you can take a look at the registration conditions of the individual registries or inquire there directly.
Delete:
When deleting, the domain is deleted at the end of the term. There are no additional costs. The consent of the domain owner is required. If this is not the case, you should set the domain to "expire".