Are you referring to a newly created document? or opening an existing one?
Was this a document that you could previously edit? and you've somehow lost that ability? or something that's never worked?
Off-hand, it sounds like the document is a Page Layout-based document, where you have to place text blocks on the page into which you add text. These differ from Word Processing-based documents that are more of a continuous flow and make assumptions on where you want the text to go.
Check File -> Convert to Page Layout and/or Convert to Word Processing to see if that makes a difference, otherwise more details are needed.