The 6th edition of the APA Publication Manual requires each page of your paper to have a uniform 1 inch or 2.54 cm margins on the left, right, top and bottom of every page, including the title page, abstract and references pages. According to the American Psychological Association website, the illustrated sample papers in the APA Publication Manual may not appear to have 1 inch margins, but these sample pages are intended to illustrate other guidelines and should not be interpreted as scale models.
APA style requires a running head, which is a shortened title listed at the top left of every page. Use your word-processing program's header feature to create your running head and don't adjust the spacing. Your running head will be in the top margin, as will the page number, which should be on the top right of the page. The American Psychological Association website explains that since the running head isn't part of the main body of text, it should be in the margin rather than below it.