Difference Between Workflow rule and Approval Process

Workflow Rules:

1. Workflow rules are Activated when record is Saved.
2. Workflow rules consist of single step and single action.
3. Workflows can be Modified,Deleted.
4. In Workflows automatic tracking of history is not available.

Approval process:

1. Approval processes are triggered explicitly when we click on submit for Approval.
2. Approval Processes consists of Multiple steps.
3. Some Attributes cannot be modified in Approval processes.
4. Approval processes must be deactivated to delete.
5. Approval History can be tracked.
6. If the record is set to "locked down" that record cannot be changed.