Ios8, how to reply to an incoming call by SMS?

Step 1: After we click "Settings-Phone" on the Apple desktop, we click the "Reply Message" option.

Step 2: You can set up three short messages here.

Second, the realization of functions.

All right, the text message is set. When we have an incoming call, we can click the "SMS" button:

Ok, we will hang up the phone automatically and then reply to the text message automatically after selecting the text message.