In June, Google AdWords began testing click to text ads and then we saw it expanded to the UK - Google announced "in the coming weeks, we’re introducing click-to-message ads to bring the efficiency and effectiveness of messaging to search ads."
You can set this up by setting up a message extension. Message extensions allow people to see your ad, click an icon, and contact you directly by text message. With one tap on your ad, people can contact you to book an appointment, get a quote, ask for information, or request a service. Message extensions can help you grow your business by giving people another option to reach you.
Tapping on the texting option launches a user’s SMS app with a pre-written message tailored to the product or service they’re interested in.
Forum discussion at Google+.
