1. Click the 'Sign Up Forms' tab in your control panel:
2. Next, either open your existing form by clicking on its name on the left, or click the 'Create A Sign Up Form' button to build a new form
3. To create your custom field, click the 'Create a New Field' button under the Fields area to the left of the sign-up form editor:
4. Name your field 'deadlinetext' and click 'next':
5. Choose 'Text input' as the input type, add 'deadlinetext' as the default value, and click 'Show' to change the visibility to 'Hide', then click 'Save Field':
If you have any questions, please let us know at email@example.com.