Is a preview of the message available to check before sending out the message?

Yes. Agents are in complete control and can preview the message before sending it. 

If a company-initiated message is needed for WhatsApp, the agent will need to access the message templates available in the text field at the bottom. Once selecting a message template, the agent will see it displayed on the text field before sending it. 

ℹ️ The same process applies to quick replies.

If the agent is communicating with the user freely - without message templates or quick replies, he/she is in complete control of the message in the text field and can review the message before pressing the send button.