Adding dashes between letters in Excel is a simple task that can be accomplished by using the following steps:

1. Open your Excel document.
2. Select the cells you want to add dashes to.
3. Click on the "Format" tab.
4. Click on the "Cells" button.
5. Under the "Number" tab, select "Text" from the Category list.
6. Click "OK".

You should now see dashes between each letter in the selected cells!