A family of Microsoft word processing software products for creating web, email, and print documents.
There are many possible reasons for unexpected white space in a document. Manual page breaks would make a page end short. "Keep with next formatting" will force text paragraphs onto the next page.
As a start, click the ¶ icon on the Home tab to display nonprinting marks. Take a screen shot and upload it in a reply here, so that we can see what you see.