"Flow isn't working" describes at least three different problems. The workflow never ran. The workflow ran and decided to do nothing. Or it ran, did something, and the result never showed up where you expected.
They look identical from the outside, and each has a completely different fix. So the first move isn't editing the workflow. It's finding out which of the three you're dealing with — and Flow already records the answer.
Open the workflow and check Run history. Everything below follows from what you find there.
If you're building a workflow for the first time rather than fixing one, start with Shopify Flow setup.
Flow's triggers, actions and plan availability change regularly. Confirm current behaviour in Shopify's own Flow documentation before relying on any specific detail here.




