Exporting PDF without margins

I've created an invoice in Numbers 3.5.3 using an 8.5x11 space. Whenever I export a PDF, it adds about .75" margins all around, creating a PDF that's much larger than 8.5x11. There are no options when exporting a PDF. Same thing happens on mobile. I want to be able to create an invoice/estimate when I'm out in the field.

Anyone know how to fix this? Thanks!