The Arrow tool is used to draw "leader lines" (multi-segment lines with an arrow at one or both ends). They are typically used to call attention to some part of your drawing. The type and size of the arrow is defined by the Arrow style option. Arrow styles are defined in the Arrow style definitions setting panel. When an arrow style definition is changed, all of the arrows in your drawing that were drawn using that style will reflect the new settings.
The options described below can be found in the bottom app bar or in the control panel.