Turn on the drawing toolbar. Draw an arrow or other drawn object. Change
the formatting of the object to your preferences. With the object still
selected, click Draw on the drawing toolbar and click Set AutoShape Defaults.
Whatever formatting has been applied to the selected object will be the
default from then on - not just for line color, but including line style,
fill color, etc.
Turn on the drawing toolbar. Draw an arrow or other drawn object. Change
the formatting of the object to your preferences. With the object still
selected, click Draw on the drawing toolbar and click Set AutoShape Defaults.
Whatever formatting has been applied to the selected object will be the
default from then on - not just for line color, but including line style,
fill color, etc.