Help & support guides for your Apple iPhone 6 Plus
Set up your phone for iMessaging
You can send iMessages to phone numbers or email addresses if the recipient has a device which supports iMessages. To set up your phone for iMessaging, you need to activate your Apple ID.
Press Settings.
Press Messages.
Press the indicator next to "iMessage" to turn on the function.
If you're an Unlimited SMS customer, you need to turn off iMessages.
Press the indicator next to "Send as SMS" to turn the function on or off.
If you turn on the function, your iMessages will be sent as text messages if the service is unavailable.