For more, see Layer Management
Located: Layer Manager
An alias can be established for a layer name if needed. For example, a layer named RD_123.shp, can have an alias of Roads, making the data layer more recognizable to any user. The alias is viewed when the mouse is held over the Layer Legend or when a legend is displayed.
To use:
To add or change a Layer Alias, open Layer Manager.
Select desired layer.
In the text box below Layer Alias, enter desired alias.