Once set up Inventory Advice's can be sent to your 3PL or Warehouse through the Item Settings page.
settings cog => Items => Item Settings
Items that have the Send Inventory Advice enabled will be sent in the report. This field can be auto configured on some ERP systems.
Select the 3PL company to send to in the bottom right and click "Send Advice".
This information can be configured to be sent automatically through task scheduler.
Please see the attached video for more information.