- Enable the Maplex Label Engine.
- Click the Label Manager button on the Labeling toolbar.
- Check the check box next to the layer you want to label.
- Choose a label class under the layer.
- Click Symbol.
- Click Edit Symbol.
- Click the Formatted Text tab.
- Type a value for the character spacing.
- Click OK to close all dialog boxes.
This will be the minimum character spacing when you choose to spread the characters in your labels.