Printing with Margin setting

How do I adjust the margin's when I print in Acrobat Reader? Right now the text is right up against the left side of a standard letter size page. I'd like to move it to the right by about a 1/2 inch. There is a very wide margin on the right. I've tried using the bordaerless button and it doesn't chage the text placement with either setting. I've been using the setting that has boardless turned off.