You may now test your PBE by sending it to any address. Initially your own address will be populated, but you can edit it by clicking on the email. To edit the test address, click on the email address and then click save icon once the other address has been entered.
Testing your PBE is important because this way you make sure everything looks the way it should before you send it out to mass amounts of people
Since there is no un-send option, testing is the last chance the sender has to confirm the e-blast meets their expectation.
Though not recommended, the sender may click the Test button, skip viewing it in their inbox and click the Send button immediately afterwards.