Turn Message Delivery Confirmation Setting On / Off - Moto X™
If SMS is disabled, ensure that SMS is set as the default app.
From a Home screen navigate: Apps > Messaging .
From the Inbox, tap Menu (located in the lower-right).
From the "TEXT (SMS) MESSAGES" and "MULTIMEDIA (MMS) MESSAGES" sections, tap Delivery reports to enable or disable.
If not available (grayed out), tap SMS Disabled (located at the top) then tap Yes.
Enabled when a check mark is present.