One-way opt-in campaigns are commonly used to opt-in for alpha numeric IDs.

SMS one-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. Click Next to move on to the next section.
4. Toggle the activate campaign option. Click Create.
5. Alternatively, you can choose not to activate the campaign right away. You can choose Create as draft.