For an APA header you need the title of your paper on the left, and the page number on the right. The header on the first page is a little different -- you need the words Running head: before the title on the title page. Here is how to do it:
You can quickly add a page number using Word's gallery. Here's how:
You'll just need to save your paper in a different format in Word. Here's how:
Now you have a copy of your paper in RTF format!
You can change the page margins in Word by choosing from one of Word’s predefined settings or by creating custom margins. Here's How: