UML or Unified Modeling Language is used mostly in the field of software engineering as a visual modeling language, which consists of a series of integrated diagrams that are used to visualize, create and record the by-products created during systems and software development. BPMN, on the other hand, is the short form of the Business Process Model and Notation.
It is a type of notation used by businesses to help their business users understand certain business processes. While the UML concentrates on a modeling software system, BPMN concentrates on business processes. Since the UML notation is centered on a modeling software system, it uses an object-oriented language.
In contrast, the BPMN, which focuses on business processes, uses a process-oriented language. The object-oriented applications or systems that are used for UML notation are applied in different areas such as commercial applications, web applications, etc. In contrast, BPMN is used mostly by IT developers, analysts, and others that focus on business processes.