On iPhone and iPad, the “Messages” app combines both capabilities. The classic Text message is shown in green, an iMessage is certainly highlighted in blue.
An Text message is directed as usual via the mobile phone network. An download imessage for pc message is sent on the internet.
An SMS could be received by every mobile phone owner. An iMessage can only just be sent to owners of Mac pc, iPhone, iPad and ipod itouch.
Your iOS unit instantly detects if the recipient can get an iMessage. If this is not the case, a classic SMS will be dispatched.
Whether you send an iMessage or an Text message, you often see in the text field (see picture).