You can customize the content for the default text message within the app by logging into the Online Sales Pro web app. From the top navigation click on the Edit tab. Click on the Autoresponder tab.
Scroll down to the Click to Email/Text App Feature section. Click on the App Text Message button. Edit the content that you'd like to be set as the default text message. Be sure to save your changes by clicking on the Update button. Log out and log back into the app to see the updates.