The easiest way is to refer to Wikipedia:
„A workflow consists of an orchestrated and repeatable pattern of activity, enabled by the systematic organization of resources into processes that transform materials, provide services, or process information. It can be depicted as a sequence of operations, the work of a person or group, the work of an organization of staff, or one or more simple or complex mechanisms.”
The non-existent as of 2019 WfMC (WorkFlow Management Coalition) coalition – please do not confuse them with martial arts – defined workflow as the automation of business processes, in whole or in part, during which documents, information or tasks are transferred from one participant to the next, according to appropriate management procedures.
More information about workflow can be found here: https://dew-x.com/pl/workflow/