4 - Use your email marketing list
If you have already built up an email marketing list, then you can use email to encourage customers to sign up for SMS notifications as well. All you need to do is ask your customers to text a specific keyword to your dedicated short code or an inbound long number. For example, we'd ask our customers to text "ReachSMS" to 60075 to opt-in.
Once you have built up your SMS list, you can then use it in sync with email. You'll be able to send texts to your customers that preps them for incoming emails. Since SMS has a 98% open rate, you can rest assured that your customers will see your message.