Element (MX00.2)
Use Element (MX00.2) to define a name that identifies the element, a description of the element, and attribute value parameters such as the data used to define the attribute (Alpha, Numeric, and Date) and the field size that determines the number of characters used to represent the attribute value. You assign an element to an attribute on Attribute (MX00.1).
Once you define values for the attribute, you cannot change the data type or field size.