On all Action Alerts that are sent to President of the United States (POTUS), you will need to set the contact field of "Phone" as a required field.
  1. Go to Advocacy > Action Alerts
  2. Find and "Edit" the desired to alert.
  3. Go to step 5, Select Contact Fields.
  4. Find and check both check boxes next to the "Phone" field.
  5. Click the "Save" or "Next" button to save.