Rush interacts with Shopify Store Admin in multiple ways:
During installation, Rush takes all your orders tracking numbers (for the last 7 days, limit enforced by Shopify) and process them in the Rush system. These are FREE of charge, as a welcome gift, but also to jump-start your Store(s) data into the Rush system.
For these Shipments, no notifications are sent from Rush's side.
If Merchant marks an Order as Fulfilled (manually or automatically using a 3rd party app / software) Rush takes the tracking number and process it instantly within the Rush App Shipments Dashboard
If Merchant uploads CSV, XLS Excel file via Rush Smart Import feature, Rush will automatically mark orders as Fulfilled and add all tracking numbers to all orders accordingly.
Rush tracking sync process:
Rush takes carrier's tracking number from the Shopify order and creates an unique key (number) e.g. RECYW85QRUSHTPMXVDBX (see image above)
When Merchant is charged?
Rush is charging per Shipment that is included in your plans quota or as part of an additional extra shipping charge based on your Cap Limit, only when shipments have real active tracking numbers that Rush can process.
NOTE: If a wrong tracking number is imported (but valid) and then it's updated for a specific order, Rush will charge for it.