In the Excel workbook, select the specific cell(s) that you want to use, and copy them to the clipboard. Go into the Word document, position the cursor where you want the information to appear, and click the down arrow on the Paste button. Choose either "Link & Keep Source Formatting" to have the cell appear the same as in Excel, or "Link & Use Destination Styles" to have it appear with the formatting of the current location in Word.
The "Link" part of this means that changes in the data in Excel will appear in the Word document, assuming that the workbook is accessible from the computer where Word is running.