Workflow (Business process) is a process of document processing with start and several output points as well as sequence of activities (steps, stages, features), performed in a specified order and under specific conditions.
In other words, Workflow is a sequence of activities, directed at achieving a planned result.
In Bitrix24, all workflows operate with elements (sometimes also referred as "documents": files, iblock and CRM elements) and their versions. Each workflow element (iblock, lists and and etc.) have its own workflow templates. The following element types are supported:
Iblock elements in Control Panel
Files from element library (Bitrix24 On-Premise)
CRM elements (Bitrix24 On-Premise)
Workflow access permissions
In majority of cases, Workflow module correct operation requires an access permission configuration and iblock settings.
When creating a workflow and selecting users inside
When handling a workflow inside activity template parameters and status settings, indicate both custom text as well as different variables, document fields and other already existing data. It is done via the Insert value special form.
it shows only the users with corresponding level of access permissions for a document type for which the workflow is created.
For example, with Read level of access permissions (assigned for specific user group inside an iblock config) users won't have access to workflow handling, albeit can view its elements.
Video materials with Bitrix24 webinars, describing the workflows feature and how to work with them based on demonstrated examples.
Note: These videos overview Bitrix24 features, but general information and principles are applicable to other products that use workflows.