You can use the Annotation shape in Process Modeler to document your flow and share comments with other developers. Annotations have no effect on processing.
In the toolbar of Process Modeler, click the Shape palette icon 
to display a menu of shapes.
Click and drag the Annotation shape to a position on the flow diagram.
Replace the default text with your notes or comments.
Press the Enter key to resize the Annotation shape to fit the text.
Tip: To create a line break in the text, enter spaces until the cursor advances to the next line. You cannot include a hard return in an annotation.