When you click on annotation and say pick out text balloon. And drag to the frame. Double click on the text. Then make sure the Properties window opens (which is open on right side opposite the action menu window)click on the A symbol:
I've had to crop some of the black space out to get the parts I want to show here. Click on Font choose what font you desire. The second window down choose formatting of the font (Regular, Bold, Italic, Underline and so on).