If you copy a table created in Excel 2010 and paste it in a Microsoft Word 2010 document, it will come with at least outside borders, if not all borders.

Open the Excel spreadsheet containing the data you want to display in your Word document. Select the data you want to appear in the Word document and press "Ctrl-C" to copy it.

Thankfully, two easy ways to convert your Word table into an Excel spreadsheet exist. The first is to copy and paste your data, and the other is to use an online converter.