Two way campaigns are commonly used to opt-in and out using a specific keyword.

Create an SMS two-way opt-in

1. Go to SMS and group messaging > Campaigns. Click Create campaign and choose SMS one-way opt-in.
2. In the Provide details section:
   1. Enter the campaign name.
   2. Select your code.
   3. Set your time zone, optionally.
   4. Enable sending hours if you'd like.
3. Click Next to move on to the next section.

   

4. Set the duration of indefinite or limited.
5. Click Next.
6. If you choose limited, you can also set pre and post launch responses here. Provide a message to be sent as a pre-launch response for day(s) before this campaign starts. And a message sent as a post-launch response after the campaign ends.
7. Click Next.
8. Create keywords and messages, including a welcome message, already enrolled message, opt-out message and help message.
9. You can set up character mapping or shorten links.
10. Click Next.
11. Toggle the activate campaign option. Click Create.
    
12. Alternatively, you can choose not to activate the campaign right away you can choose Create as draft.