If you have moved on to Android or Windows Phone from an iPhone, you most probably have missed out a lot of SMSes from your iPhone friends as their device still think that you are on iOS and were sending you iMessages which you cannot receive on your current devices.
If you wish to deactivate your phone number from iMessage and start receving SMSes again, Apple has released a tool to help you do just that.
You may need to turn off iMessage if you are now using a non-Apple phone and can’t get SMS or text messages someone sends you from an iPhone.
The page has step-by-step guide for those who are already on a new device and those who are still on iPhone. You may click below if you wish to detach your phone number from iMessage.