How to Create Mail Merge Labels in Word 2003-2019 & Office 365 Oct 09, 2020 · Maestro Label Designer and Microsoft word accept .csv, .txt, .xls, and .xlsx file formats. Microsoft Word also accepts Outlook and Apple contact lists. Step 1: Create your data list. Before Microsoft Word 2007 can auto-fill your labels, it has to access your data. If you already have your data set, move on to Step 2.