How to add a component to PDF?

(see attached screenshot)

We would like the ability to have "Account No. (office use only)" appear on the completed PDF's. However at this point it does not appear because the customer completing the form does not enter anything in that section. 

Thanks!

You may require the field, so the user must enter the number:

If you want that number to be automatically generated, you can use the Unique ID widget: http://www.jotform.com/help/79-Add-Custom-Unique-IDs-to-your-Form-Submissions

Let us know if you need more help.

We want to put a specific number in that field for each new account once the form has been completed. Therefore it would be useful to have that section appear on the PDF regardless of it being empty for admin purposes. Is that possible?

Try allowing the PDF file to show empty fields, while on the submissions page you only need to click on the settings icon and then un-check the option Auto hide empty fields. 

The field will be shown even if it is empty.