<v:line style="position:relative" from="0,0" to="100,0" >
    <v:stroke EndArrow="Classic"/>
</v:line>
    
*********************you can select the diffrent type of the Arrow from the list:
    EndArrow="Block":
    EndArrow="Classic":
    EndArrow="Diamond":
    StartArrow="Oval":
    StartArrow="Open":