Hi,
You could change the position of annotation by changing the X and Y properties of the annotations. These values represent the values relative to the whole figure and the units are normalized.
You could try to assign the "Y" property value of annotation less to make the annotation come down towards X axis and change the "X" property accordingly to make sure the annotation points at the right points.
x = 0:pi/100:2*pi;
y = sin(x);
plot(x,y)
hold on
%ar1 for first annotation
ar1 = annotation('arrow',[0.3 0.3],[0.05 0.1]);
c = ar1.Color;
ar1.Color = 'red';
ar1.HeadStyle = 'plain';
hold on
%ar2 for second annotation
ar2 = annotation('arrow',[0.83 0.83],[0.05 0.1]);
c = ar2.Color;
ar2.Color = 'red';
ar2.HeadStyle = 'plain';
Refer to the following link to know more about the properties of annotations
