To enable annual recurring donations as an option on your form, simply follow these steps:

1. Log into Donorbox with your Organisation login details and go to your dashboard. 

2. Click the Edit link for your campaign form, as shown:

3. Next, go to the Advanced tab of the form builder. All the available recurring donations will be shown under the section marked Donation Intervals. Select the box marked "Annually", so that a blue tick appears in it. This will add the Annual option to your donation forms.

4. Select "Save and Next". The Annual recurring option will now appear on your donation form.