How to set up iphone to send SMS for free?

Open the settings of iphonex;

Step two:

Slide your finger to find the information and click enter;

Step 3:

Click the button next to the iMessage message to open it;

Step 4:

Then we can open the SMS and send an iMessage message to our friends. If you don't want to use iMessage, we can come back here and close the button.