How do I know if my message has been sent?

Go to your Outbox on the left navigation panel. There you will see a list of messages you have sent out. To see a delivery report of the message you sent, click on View Report next to the message.

You can click on each option or toggle the drop-down menu to see to who the message was delivered. If it has bounced, this means that the number cannot receive text messages from your short code or they may need to opt-in by texting in your keyword.