A object containing UserProperty objects that represent the custom properties of an Outlook item.
Using The UserProperties Object
Use the UserProperties property to return the UserProperties object for an Outlook item.
Use the Add method to create a new UserProperty for an item and add it to the UserProperties object. The Add method allows you to specify a name and type for the new property. The following example adds a custom text property named MyPropName to
Set myProp = myItem.UserProperties.Add("MyPropName", olText)
Use UserProperties(index), where index is a name or index number, to return a single UserProperty object.
When you create a custom property, a field is added in the folder that contains the item (using the same name as the property). That field can be used as a column in folder views.