Magento_PurchaseOrderRule
Overview
 The PurchaseOrderRule module contains functionality for creating and enforcing approval rules for purchase orders. Companies in a B2B environment can use these rules to enforce purchasing guidelines and limits.  With this module installed, you may create rules such as: 
- Purchase orders over $X require approvals from a manager.
 - Purchase orders containing more than $Y unique products require approval.
 - Purchase orders with shipping charges greater than $Z require approval. 
 
Installation details
 The PurchaseOrderRule module has dependencies on the following modules: 
- Magento_Company
 - Magento_Customer
 - Magento_Directory
 - Magento_Payment
 - Magento_PurchaseOrder
 - Magento_Quote
 - Magento_Rule
 - Magento_SalesRule
 - Magento_Shipping
 - Magento_Theme
 - Magento_Ui 
 
which must be installed and enabled first. This module does not create any backward incompatible changes. It can be uninstalled or deactivated at any time. 
Structure
 Learn about a typical file structure for a Magento 2 module. 
Extensibility
Extension developers can interact with the Magento_PurchaseOrderRule module. For more information about the Magento extension mechanism, see Magento plug-ins.
The Magento dependency injection mechanism enables you to override the functionality of the Magento_PurchaseOrderRule module.
Layouts
This module introduces the following layouts and layout handles in the view/frontend/layout directory:
purchaseorderrule_create_indexpurchaseorderrule_edit_indexpurchaseorderrule_formpurchaseorderrule_index_index
UI components
You can extend the purchase order rule listings using the purchase_order_rule_listing.xml and require_my_approval_purchaseorder_listing.xml configuration files.
Additional information
 Check the B2B release notes for more information on new changes.