The order system default implementation contains many classes that you can extend with your own fields. This means that you can customize fields to all order objects to help with your business use cases.
Classes in this topic are available in the Mediachase.Commerce.Orders namespace. The order classes that you can extend are:
Cart
PurchaseOrder
PaymentPlan
OrderForm
Payment
Shipment
LineItem
OrderGroupAddressType
## Configure a meta-class
**Version 10-13**
In the **Commerce Manager ** **Administration** section, navigate to the **Order System/Meta Class** node.
From the **Element** drop-down list, select the correct group type.
From the **Type** list, select the meta-class you want to configure. Only the **OrderGroup** and **Payment** group types have multiple type options. Edit meta-class definitions by enabling checkboxes associated with fields you want to associate with each meta-class.
To add meta-fields, click the **Order System/Meta Fields** node and select **New/Meta Field**.
## Work with metadata types
The default implementation uses Mediachase.MetaDataPlus for its storage of extended attributes. Â The list of available types for use in IExtendedProperties.Properties are represented in Mediachase.MetaDataPlus.Configurator.MetaDataType.
<caption><strong>Supported Types</strong></caption>| **MetaDataType** | **.NET Type** | | --- | --- | | MetaDataType.DateTime | DateTime | | MetaDataType.Date | DateTime | | MetaDataType.DictionarySingleValue | MetaDictionaryItem | | MetaDataType.EnumSingleValue | MetaDictionaryItem | | MetaDataType.Float | double | | MetaDataType.Decimal | decimal | | MetaDataType.Money | decimal | | MetaDataType.Integer | int | | MetaDataType.DictionaryMultiValue | MetaDictionaryItem[] | | MetaDataType.EnumMultiValue | MetaDictionaryItem[] | | MetaDataType.StringDictionary | MetaStringDictionary | | MetaDataType.Boolean | bool | | boolMetaDataType.Email | string | | MetaDataType.URL | string | | MetaDataType.ShortString | string | | MetaDataType.LongString | string | | MetaDataType.LongHtmlString | string | | MetaDataType.File | MetaFile | | MetaDataType.ImageFile | MetaFile |
## Access order metadata
When determining if an object has extended properties, see if the interface derives from EPiServer.Commerce.Storage.IExtendedProperties.
## Set order metadata
When determining if an object has extended properties, see if the interface derives from EPiServer.Commerce.Storage.IExtendedProperties.
## Access order metadata [Legacy]
To access order meta-objects, each order meta-class has a dictionary of meta-fields accessible by the root object.
**Example:Â **accessing meta-fields from different order meta-fields