You can find a selection of fully editable arrow and flowline designs in the Line & Arrow folder. Simply click Shape on the left hand toolbar, All > will display all the current SmartShapes.
With the Arrow shapes you can adjust...
Width
Curvature
Size
Position of the arrow
Some of the arrows can also be changed to use a variety of different head and tail designs. Just drag on the handles or hover over the handles to see a tool tip description.
The Flowlines are great for diagrams, exploded views, flowcharts etc.
There are several to choose from. As with all the ‘SmartShapes’ just click / tap on them to show the edit handles.
Arrows are imported to match any Theme Color 1 you have defined (so they will match the main color of your document). Other Shapes are typically imported gray, but in either case you can easily change the color by selecting the item and clicking the color patch on the Properties panel.
Check out this movie for more on editing arrows, and other SmartShapes: