You may already have a database with your customers’ contact info. This is a great resource, however, customers have to willingly and knowingly sign up for an automated text service, you can’t just send out your first text assuming they want to participate. There are some ways you can use phone numbers to help people sign up. If you are using their phone number anyway to remind them of an appointment, tell them their product/service is ready to be picked up or send them tracking information on something that they ordered; you can add the option for them to sign up for automatic alerts and even tell them you’re switching to an automated system so if they want to continue to get reminders etc, they need to sign up using the keyword.
For more information about legal requirements for SMS Marketing and how to work within the law to build your list, check out Legal blog in the Related Content Sidebar.