What does the Preview mail-out button do?
The Preview mail-out button lets you send a mail-out to the your email address so that you can see exactly what a recipient would see should you have clicked the send mail-out button.
Everything in the Create a new mail-out form will remain there for you so you can send the mail-out to the recipient(s) selected in the Total recipients field.
There will be nothing recorded in the Tracking section from doing this preview.