To create a campaign with a form that only allows entry via a unique code, you’ll want to edit your form and add the field “Single Use Codes” to it.
When managing your offer, click “customize” on the left sidebar, which brings you to your entry page customizations. Select your form by clicking anywhere on the form.
*Note: If you don’t have a form, click “elements” and add one to your entry page.
When you click your form, you’ll see the option “settings” on the left side, click that and then choose “add form field”.
Next, select “Single Use Codes “.
Then add in your codes by copying and pasting or by uploading a file with codes (copying or pasting codes require codes be one per line).
Now users will have to have one of the unique codes you put into this setting to enter. That unique code can only be used once per form submission.