Hi Mat,
Thank you for your interest in essential PDF. It is possible to add a border to page with the help of Canvas. We can add a canvas and give size that we want. Once the canvas is added, its border will be displayed on the page.
// Add a canvas.
ICanvas canvas = paragraph.AppendCanvas(new SizeF(565,810));
Here is the sample for your reference.
PageBorder.zip
Could you please take a look at this and let me know if you have any other queries.
Regards,
Prakash