The following pages of the double-sided document will automatically flip the margin for the holes back and forth to account for the document being printed on the front and back. The last margin is the one placed between columns when you have two or more vertical parallel columns of text on a page. You can select any number of columns. Remember, however, that the larger the number of columns you select and the bigger the size of the margins, the smaller amount of information that will be presented to your reader on each page. This sounds like it would be a good way to blow up the apparent size of your offering, but remember, the smaller the width of the columns you choose will make it harder and harder for the reader to scan and understand the information.
Justification determines how the text is placed on each line in the document.
This places the first letter of the first word on each line at the left margin of the document. The last letter of the last full word on the line will be at, or to the left of, the right margin. This gives a ragged appearing right margin. The first letter of the first word on the line will be at, or to the right of, the left margin. This gives a ragged appearing left margin.