Hello!
Thanks for your interest in CryptPad!
Due to how guests are currently handled, it's not possible to certify who created the document.Hence, the impossibility to delete it yourself.
If it contains private information that needs to be deleted you can reach out to your instance administrators, giving them the Document identifier
and asking for its deletion.
Otherwise, if no one access the file for a while, it will ultimately be archived and then deleted. But these retention settings can be customized for every instance and may differ from one to another.