Locate the column with the cell phone icon (next to the Renewal Date column). Numbers with a checkmark in this column can be used for text messaging in your account.
Numbers that support texting must be text-enabled before you can send and receive texts. Always refer to your Text Numbers page to see which numbers are enabled. Numbers that are ported over to CallTrackingMetrics must already be text-enabled to send/receive messages.
In the Incoming Text Messages and Outgoing Text Messages sections, the numbers in the list on the right are currently enabled for texts. Click the numbers in the list on the left to move them to the list of text-enabled numbers on the right.