A mail merge is a great time-saver for when you need to print out a series of personalized letters, envelopes, or mailing labels. This introductory guide to mail merge will walk you through how to use Microsoft Word and an Excel-based list to create a customized letter, envelope, or mailing label.The guide is written using Office 2013 and assumes a basic understanding of Microsoft Word and Microsoft Excel. If you're not familiar with one or the other, you should probably start with Word for Beginners and/or Excel for Beginners first.