I've created a photoshop design for an invoice. The invoice design fits perfectly on the Word page, but when I print the exact example, it prints with white borders of 2 cm. Is there maybe an option to disable the margin so my invoice design fits perfectly on the paper?
Your printer might be able to print on the entire paper in theory but I wouldn't recommend it. It gives a lot of trouble.
I work with printing and normally you would either print on a larger paper size and then cut it to its intended size or you would make a design with a white margin.
In your case i would either live with it, print it a little bit smaller and cut it or redesign it without color exceeding the paper.