The reference ID label represents a universal field that can be referenced in your account. As an example, the label of the reference ID could be an 'Account Number' that is associated with each customer. The customer Account Number will then be available throughout your account. If a custom label is not set, it will automatically appear as Reference ID.
To change the label for reference ID enter a new label as it should appear throughout your account and then click the save button that is located in your Settings menu under Basic Settings