When you add a contact to your account, they must opt-in to receive text messages from you before you can send to them. To opt-in, they receive a text asking them to opt-in to receiving text message reminders.
The default opt-in text message includes a customized link with a message that reads:
Receive texts from OllieBot? Tap link to respond. Reply STOP to unsubscribe
If your plan includes branded messaging, you can customize the message that gets sent in this text. To do this, visit your profile settings, input a value for "Verification Prefix", and click "Update". This will overwrite the "Receive texts from OllieBot?" text that goes out. Test this out by adding yourself as a contact.
If you have more questions, please contact us.