An SMS only has 160 characters. This means you need to be quick when you are sending messages to people and not use too many words. Try not to make your SMS longer than this because they will be harder to read and your participants might only receive half of the message if they do not have a smart phone.
Your message will have more impact if you don’t waste characters by writing long greetings such as ‘Hello. How are you? I hope you are fine!’ If you greet people you won’t have any space left for the rest of your message.