1. Select Manage > Contacts.
2. Click on Mailing Lists to the right.
3. Click the arrow on the SMS Mailing List that you want to set up the Opt-in Keyword option for.
4. From the dropdown menu, select the Opt-in Keywords option.
5. Click the ‘Create An Op-In Keyword’ button and then the following window will be displayed. Start by adding the keyword that the contacts will need to include in their SMS in order to Opt-in to the Mailing List.
7. Add the response you want to have automatically sent to anyone who’s Opted-in to the Mailing List. Please note: you will need to have enough SMS credits on the account the Mailing List is set up on to facilitate this. For SMS pricing, please click on the cog icon in the top right of the dashboard and then select Extras and Add-ons.
8. Once you’re happy with the settings, click the Save button.