For added security, RMail provides an option to Convert to PDF format as well as encrypt any Microsoft Office attachments with one click en-route and add password protect the attachment.
When this feature is enabled, the sender will be asked to pick a custom PDF Password for the recipient to enter before viewing the password protected PDF. The sender will need to provide the recipient with this password.
Note: The email body will be viewed in the recipient’s mailbox without a password required.
The attachment in the “Sent Items” folder remains in the native format and does not require a password to open or view.