Configure Magento settings

Go to Stores > Configuration > Sales > Order Numbers to configure your chosen settings in Magento.

Invoice/Shipment/Creditmemo Prefix (v1.0.0+)

Choose a prefix for your invoices (e.g. INV-), shipment (e.g. SHIP-) and credit memo (e.g. CREDIT-) numbers. 

How To Use The Extension

Once installed, all new invoices, shipments and credit memos will be automatically assigned the same number as the related order. For example, for order #1000, the associated invoice would be #1000, the shipment #1000, and the credit memo also #1000.

In the event that there are multiple invoices, shipments and/or credit memos associated with the same order, duplicate separation will happen automatically. For example, the first invoice would be #1000, the second #1000-1, the third #1000-2, and so on.