The Vonage Go SDK is used to send an SMS using Go in less than 20 lines of code, requiring only a Golang installation or access to the Golang Playground. The SDK provides a simple and secure way to create an auth object combining API key and secret, instantiate an smsClient object, and perform actions on the Vonage API such as sending an SMS. To send an SMS, you need to pass the necessary information including the number the SMS should be sent to, the number it is sent from, and the text to be displayed. The heavy lifting of sending the SMS is done in a single line using the Send method provided by the API client, with error checking and response output added for verification.