SMS is an abbreviation for Short Messaging Service which is most commonly referred as a text message or texting. Unlike Instant Messaging which uses the internet to send quick messages, SMS relies on both phones having good signal or with roaming service capability as without it, you won’t be able to receive or send any messages. The reason for it being called ‘short’ messaging services is because it allows you to send text messages with only 160 characters. If you do not have credit or signal then your text message will not send and a red explanation mark will pop up next to your message.
People use SMS for more personal uses rather than business purposes unless you have a business phone. Personally, I use SMS when messaging my friends and family as I do not like texting anyone related to work unless it is my supervisor.