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If you already have a spreadsheet containing the names and addresses for your labels, follow along with these steps to make sure it's set up in a format that works with Microsoft Word's address merging feature.  In Windows, click the Start {"smallUrl":"https:\/\/www.wikihow.com\/images\/0\/07\/Windowsstart.png","bigUrl":"\/images\/thumb\/0\/07\/Windowsstart.png\/30px-Windowsstart.png","smallWidth":460,"smallHeight":460,"bigWidth":"30","bigHeight":"30","licensing":"<div class=\"mw-parser-output\"><p>I edited this screenshot of a Windows icon.\n<\/p><p>License: <a rel=\"nofollow\" class=\"external text\" href=\"http:\/\/en.wikipedia.org\/wiki\/Public_domain\">Public Domain<\/a><br>\n<\/p><\/div>"} menu, select All Apps, open Microsoft Office, then click Microsoft Excel. If you have a Mac, open the Launchpad, then click Microsoft Excel. It may be in a folder called Microsoft Office. The first row in the sheet must contain header for each type of data.  For example, LastName, FirstName, Title, Address1, Address2, City, State, Postal Code, Country. Each of these headers would go into its own cell in Row 1. Each column header must be unique so there's no issues with the merge. Each row must contain the information for one person. For example, if you’re adding Ellen Roth as the first person in your address list, and you’re using the example column names above, type Roth into the first cell under LastName (A2), Ellen into the cell under FirstName (B2), her title in B3, the first part of her address in B4, the second (if there is one) in B4, etc. It’s important that each person’s information matches the column header.  It’s okay to a cell blank (for example, if the person’s address does not need the “Address2” field), but there should be no entire blank rows in your data.  There’s no need to use any special formatting, such as cell colors or special borders, in your data. Only the data in the cells will be used. After you’ve entered all of the addresses for your labels, you’ll need to save the file so it can be imported into Word. Click the File menu, select Save As, then type a name for your data. When you’re finished, click Save. Remember where you saved this file, as you'll need to be able to find it when it comes time to import it into Word.

Summary:
Open Microsoft Excel on your PC or Mac. Enter field names for each column on the first row. Enter the first person’s details onto the next row. Continue entering names and addresses in this format. Save your sheet.