A family of Microsoft word processing software products for creating web, email, and print documents.
The solution is to turn off the Design Mode button on the Developer ribbon:
Explanation: When you use the Page Number button on the Insert ribbon or on the Header & Footer ribbon to insert a "Top of Page" or "Bottom of Page" page number, it's inserted in a content control. When the Design Mode button is turned on, you'll see the blue boxes that indicate the presence of the content control. Turning off Design Mode makes the boxes invisible. The same thing is true for citations, except that there's no text inside the boxes.