AutoSize Property
AutoSize property as it applies to the CheckBox object.
AutoSize property as it applies to the TextFrame object.
Returns or sets a Long that represents whether a text frame is sized automatically. Read/write.
expression.AutoSize
expression Required. An expression that returns a TextFrame object.
Example
This example sets the size of the check box named "Check1" to Auto and then selects the check box.
With ActiveDocument.FormFields("Check1").CheckBox
.AutoSize = True
.Value = True
End With