At this time we only have TLS encryption for our outgoing mail cluster, incoming mail is not encrypted yet. If you require TLS encryption for both incoming and outgoing e-mail I would recommend an office365 or G Suite subscription.

Links are below to sign up to that service.

https://gsuite.google.co.nz/intl/en_nz/
https://products.office.com/en-nz/business/small-business-solutions

To setup:

https://www.wpbeginner.com/beginners-guide/how-to-setup-a-professional-email-address-with-gmail-and-google-apps/