Larry is a mobile notary, and some companies want him to provide his private information via email. He doesn't want to do that. Leo says you shouldn't because it's not secure with servers that are between you and them. What Leo recommends is ZIPPING it with a password, then send them the password to them by phone.
Firefox also has a service called FireFox Send, which would enable you to send documents with a secure link that will expire after a brief time. ShareFile is another option.