Following Order Status Workflow will help you understanding how the progress process is when an order is created by customer. Otherwise, the order status workflow will point to store admin that each order status is corresponding to a state.
For example, the first stage of a new order that is not paid and shipped, Magento 2 system will auto-set it to “Pending”. After you complete an invoice or you update the shipment the status is changed to “Processing”, and when you both generate an invoice and you ship the order the status is changed to “Complete”.
Let have a detailed view of the order status workflow with the chart below.
Ref: Magento 2 User Guide
It comes to the end of tutorial: Order Status Workflow in Magento 2.