Workflow is defined as a series of sequential tasks that need to be completed in order to reach a certain goal.
A workflow in JIRA is defined as a series of sequential tasks (such as create/open a bug, Work in progress, and completed/closed) involved in the life cycle of a bug or an issue.
Create: Create an issue or bug
Work in progress: Series of actions performed to fix the issue
Closed: Completion of the issue after verification