Install Gmail SMS Alerts from Chrome Web Store.
How to get started and troubleshoot this extension is explained in support note.
Gmail SMS Alerts
Mobile Text Alerts for Gmail: FAQ (Frequently Asked Questions)
Examine responses to frequently asked questions about Mobile Text Alerts for Gmail .
How to send and receive SMS messages using cloudHQ extension?
cloudHQ provides the following extensions to send and receive SMS messages: Gmail SMS Alerts, Gmail Phone, and Gmail Phone