Adding a purchase reference to an invoice

How do I add a purchase reference to an invoice as once I add the number it is not showing on the final invoice?

Go to Account Settings > Invoice Style > Invoice Labels and make sure Purchase Reference option is ticked

Thanks but I have an old style invoice template that was created by the Quickfile team due to various requirements and it looks like i would need to change everything to get on to a new style invoice design. I was wondering whether I was missing a simple tick box elsewhere?

you dont need to alter invoice design, just click on invoice label box under invoice style

You star, than you so much!!

Also covered here for future reference:

http://community.quickfile.co.uk/t/purchase-order-reference-not-showing-on-invoice/826