SMS stands for Short Message Service. It is a text messaging service that allows the exchange of short text messages between mobile devices, typically limited to 160 characters per message

. SMS messages are sent over cellular networks using signaling channels and do not require internet connectivity, making them widely supported and reliable even in areas with limited network coverage

. SMS is commonly known as texting and is used for personal communication as well as business purposes such as marketing, two-factor authentication, and mobile banking

. It was developed as part of the GSM standards and has been in use since the early 1990s

. In contrast to SMS, MMS (Multimedia Messaging Service) allows sending messages with multimedia content like pictures, videos, or audio, and supports longer text messages

. In summary, SMS is a basic text messaging service for sending short text- only messages between mobile phones without requiring internet access