Install a PDF driver that supports borderless PDF documents.
NOTE: A borderless PDF on your screen does not mean that your printer also supports borderless printing. To do so, you will need a printer that supports this feature.
On Apple computers, you can set up border parameters for PDFs in the print dialog. Because most printers do not support borderless printing, the default parameters on your Mac is with borders. For example, standard A4 pages are created with 2 cm borders on each side. That goes for PDFs as well.
You can create your own paper size to avoid these restrictions. Open the print dialog box, then select "Manage Custom Sizes..." in the "Paper Size" menu to create your own paper size. For a borderless A4 page, choose 210 mm x 297 mm as paper size and 0 mm of non-printable area on all sides. Look at the screenshots below to see how this is done.
NOTE: A borderless PDF on your screen does not mean that your printer also supports borderless printing. To do so, you will need a printer that supports this feature.