Workflow rules, processes, and flows are all Salesforce tools for automating business operations. They do, however, work differently and have various objectives.
Workflow rules are used to automatically initiate an action when specific conditions are satisfied. You could, for example, design a workflow rule that sends an email to a client whenever a new account is created. Workflow rules are commonly used to automate simple tasks like sending an email or creating a task.
Processes are used to automate more complex processes with several steps and multiple persons. A process can be started or stopped by a variety of events, such as the creation or modification of a record or the completion of a job. Processes allow you to specify different actions that should be taken based on different conditions, and they can include elements such as approval processes and field updates.
Flows are used to automate processes that involve multiple decisions and branching logic. Flows can be used to guide users through a process, to collect input from users, or to make decisions based on user input. Flows can be triggered by a variety of events and can be used to automate processes that are too complex to be handled by workflow rules or processes.
In summary, workflow rules are used to automate simple actions, processes are used to automate complex processes, and flows are used to automate processes that involve multiple decisions and branching logic.