Call-to-Action
This field is for a description of how your contacts opt-in or how consent is obtained. Just as there are virtually countless SMS/MMS use-cases, there are many different ways that consent for messaging can be obtained, including through a website, a user-initiated text (called a Mobile-Originated or MO message) to the brand, verbally, telephone calls and many others. Please describe how you're getting your leads/prospects/contacts to opt-in and give consent to SMS.
An example:
The contact fills out a form on our website where they can consent to receive notification messages. There is also a box they can check to receive product updates and/or marketing messages. The messaging disclosure is displayed to users by this form.