Menu: View→Object Properties→Text→Variable label
A label associated with the currently selected variable. A variable's label can be different from its name. If a variable has a label, its label appears on the path diagram. If a variable has no label, its name appears on the path diagram. Changes made in this box are reflected immediately in the path diagram.
Programming
In Amos Graphics programs, you can fill this text box with "Sample text" by using the following statement (Visual Basic):
pd.GetTextBox("ObjectPropertiesForm", "VariableText_1").Text = "Sample text"