How to draw an arrow

Try there

https://book.mql4.com/functions/objects

Should draw a up and down arrow on every tick.

int i;

i=Bars;

name = "Dn"-i;

ObjectCreate(name, OBJ_ARROW, 0, Time[a], High[a]+20*Point); //draw an up arrow
ObjectSet(name, OBJPROP_STYLE, STYLE_SOLID);
ObjectSet(name, OBJPROP_ARROWCODE, SYMBOL_ARROWUP);
ObjectSet(name, OBJPROP_COLOR,Blue);

name2 = "Dn"+i;
ObjectCreate(name2,OBJ_ARROW, 0, Time[a], Low[a]-20*Point); //draw a dn arrow
ObjectSet(name2, OBJPROP_STYLE, STYLE_SOLID);
ObjectSet(name2, OBJPROP_ARROWCODE, SYMBOL_ARROWDOWN);
ObjectSet(name2, OBJPROP_COLOR,Red);