To forward a text message using the native Messages app, all you have to do is tap and hold on the message to be forwarded. You should see "copy" and "More...". Select "More..." Afterwards, the message will have a checkmark in front of it. At the bottom of the screen, you will see an icon of a trashcan on the left and an arrow icon on the right. Select the arrow icon and then enter the recipient to whom the message will be forwarded to. Tap on "Send". Voila!!