Mailing Sub options showing grayed out in word file This grayed out options will be enabled when you use the Mail Merge feature in Word. For example, to start the Mail Merge with an Excel file, please follow: 1. In Word, choose File > New > Blank document. 2. On the Mailings tab, in the Start Mail merge group, choose Start Mail Merge, and then choose the kind of merge you want to run. 3.