BPMN#
BPMN (Business Process Modelling Notation) is an open standard for documenting business processes.
Documentation#
Business Process Modelling Notation - BPMN (Wikipedia)
BPMN-reference documentation (Very useful symbol-reference and applied examples)
Online modeling tools#
You may use any tool you please, to produce your BPMN-2.0 diagrams.
Below are free recommended tools: