You need a mail document in Word and the Excel workbook that contains the data you want to merge. In this case, it’s the address records in the sheet named Mail.

Perhaps the easiest way to find duplicates is to use Excel’s advanced filter. It’s flexible and can easily find duplicate rows. What you do with the result is up to you.

How to Replace Duplicate Letters in Excel. Using the find and replace ability in Microsoft Excel 2010, you can quickly replace duplicate letters, words and cells in a spreadsheet document of any size.

Just copy the content from the Excel Sheet and paste it in the Word Document. Choose the option Keep Source Formatting and Link to Excel or Match Destination Table Style and Link to Excel option ...