THE MEDIUM IS OUR POST

Transmitter to receiver, which leads back to feedback , +-5%
Email is used when requested, which is close to mail mail
Write a card for someone in a envelope who will read it which is the USPS mail

• someone taking time to write something 
• through a text its as if its not important

Spelling, grammar is important in an email

There is also a two verification to know if its you, passwords should be changed 3 days

Proton mail is easily with good access of passwords secured and information 

The channel in which is appropriate and secure would be the ones with two identification code access either through mail or phone number or by message.