Adding Hyphens to a 9 Digit Zip Code Column in Excel

1. Select the column with the zip codes that you want to add hyphens to.
2. Click on the "Find & Replace" button in the "Editing" section of the "Home" tab.
3. In the "Find and Replace" dialog box, click on the "Replace" tab.
4. In the "Find what" field, enter the last 4 digits of the zip code without a hyphen (e.g. 1234).
5. In the "Replace with" field, enter the same 4 digits with a hyphen before them (e.g. -1234).
6. Click on the "Replace All" button.

This will add a hyphen before the last 4 digits of all the zip codes in the selected column. Now you can use this column in your mail merge without having to manually add the hyphens.