On iPhone and iPad, the “Messages” application combines both functions. The classic Text message is displayed in green, an iMessage is definitely highlighted in blue.
An SMS is directed as typical via the mobile phone network. An imessage for windows communication is sent over the Internet.
An SMS could be received by every mobile phone owner. An iMessage can only be delivered to owners of Macintosh, iPhone, iPad and ipod itouch.
Your iOS machine instantly detects if the recipient can get an iMessage. If this is not the case, a classic Text message will be delivered.
Whether you send an iMessage or an SMS, you generally see in the written text field (see photo).