In your document, you have to account for the margins (space for borders) that will help you see what the final print will look like. For example, a regular 8 1/2 x 11 '' word document, by default, has a 1'' margin around the document to make sure the writing doesn't get cut off when it is printed.
In digital lingo, we say to add bleed, trim, crop marks & live/safe area to our document, if needed