Email encryption ensures that confidential information remains secure by converting the email content into cipher text. Digital signatures provide a method to check the integrity of the email, confirming that it has not been tampered with. Combining both encryption and digital signatures is the best way to secure email messages, ensuring confidentiality and integrity throughout transit. Regular data backups are crucial for recovery in the event of data loss but do not secure emails in transit. Two-factor authentication adds a layer of security for accessing email accounts but does not protect the contents of individual emails.