You can start a workflow automatically based on the condition you set
You will find the setting in the Division and then editing a Workflow
Firstly switch it to On.
Then set your condition as shown above - typically these will be the Value or perhaps who raised the order (Originator) or say who the supplier is.
This is effectively the entry point of the workflow.
Create your workflow or edit is as required. You can use conditions on each step as well.
Then finally set the default workflow for Orders to Automatic as shown below or Invoice Automatic Invoice Workflow
When the user creates a Purchase Requisition, or someone process an Invoice, the choice of workflow will be automatic based on the first matching condition - the first workflow with a matching entry point will be used.
Make sure you don’t have any overlaps in your entry points though.