I used to teach the MS Office Suite in college classes. As a few others have mentioned it it the end-of-paragraph mark and is placed at the end of every paragraph. I also appears on blank lines, since they constitute a paragraph to Word. To turn them off so they no longer appear in your document you should see a button on one of the tool bars at the top of the screen which has the same symbol on it. Just click on that button to turn them off, or back on again. A lot of professional typists keep them on so they can tell what's going on in their document. Word Perfect used to imbed a lot of these hidden codes to control aspects of a document.
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