You will need the Full Write Workflows permission to perform this action.
Click Automation > Workflows from the left navigation menu. Then scroll or search for your chosen workflow by name. From the Workflows listing, you can click the 3-dots menu at the front of the row and select Delete.
You can also delete by clicking on the name of the Workflow and then clicking Actions > Delete.
A pop-up confirmation message will appear. Enter the phrase indicated and click Confirm Delete to finish.
Helpful Tips
All tasks in the workflow will be deleted and any linked forms or workflows will become unlinked.
Any people who were currently in the workflow will also be removed. Their person profile will not be deleted, and the history of what happened in the workflow will still be kept on their profile.