time = 0.0:0.001:1.0;
y = sin(2 * pi * 2 .* time);

hold on
fig = figure();
fig.PaperUnits = 'centimeters';
fig.PaperSize = [4 4];
fig.PaperPosition = [0.0 0.0 4, 4];
fig.Color = 'white';

plot(time, y)
plot([0.0 1.0], [0.0 0.0], '--', 'color','k', 'linewidth', 0.75)
xlim([0, 1.0])
ylim([-1.5 1.5])
text(0.85, -1.2, 'a text', 'Fontsize', 7, 'Color', 'red')
annotation('textarrow', [0.45 0.75], [0.2 0.225], 'String', 'look here', ...
    'Fontsize', 7, 'HeadWidth', 2, 'HeadLength', 2);

annotation('doublearrow', [0.22 0.62], [0.8 0.8], ...
    'Head1Width', 2, 'Head1Length', 2, 'Head2Width', 2, 'Head2Length', 2);

saveas(gcf, 'annotations', 'pdf')