CivicSend does not have an archive for messages. However, you can prevent messages from being public by assigning them an expiration date. This article shows how to use the Message Expiration option.
Instructions
Navigate to Modules and select Content. Then click CivicSend:

Navigate to the Message Type section. Follow the instructions to create a Template Message in CivicSend:

Select the box next to Want Your Message to have a Public Expiration Date?:

Click on the Stop Public Display on field:

Select a Message Expiration Date:

Ensure that everything is correct, and select Send Now to send the message:
