Q. How do I add a page number to my document in Google Docs?

In your Google document, 

1. Click Insert
2. Find # Page Numbers in the list (towards the end)
3. Select the placement of page number you need. 
   1. The first option, "page number in header starting on the first page," is what you want for MLA and APA.
      1. For MLA, after you add the number, double-click in front of it to write your last name. Don't forget to make the font match your document!
   2. The second option, "page number in header starting on the second page," is good for Chicago Style.

Alternate Way

1. Double-click in the header space of your document -- the top inch or so, above where you can start writing content.
2. Click Options
3. Select Page numbers
4. In the Page numbers menu, choose how you want page numbers added. You want them in the header, starting with 1. 
   1. For MLA and APA, leave "show on first page" checked.
      1. For MLA, after you've added the page number, click in front of the number to add your last name.
   2. For Chicago style, uncheck the "show on first page" option.