To send a private email, simply compose the email as normal but include '#private' anywhere within the email subject or body. Then hit ‘Send’ just like normal. The email and any attachments will automatically be encrypted. Emails sent to personal email accounts (and business accounts which do not support TLS email) will be encrypted and the recipient will receive a notification email - for more information, see here. Emails sent to business accounts will be encrypted using TLS email encryption. 

You can also send emails where only the attachments are encrypted by including '#private#reduced' anywhere within the email subject or body.

Below is an example email using #private: