The Callout tab of the Dimensions dialog box lets you set options affecting a callout line's appearance. If you set callout options (and other options, such as font size) when nothing is selected, the defaults are changed. All callouts you draw afterwards use the new settings. If you set options when an object is selected, only that object is changed; the default settings are not changed.
The Style option lets you set how the callout text is displayed, such as in a box or circle. You can select the following styles:
The Inner Margin box specifies the amount of space between callout text and the border. Increase this value to place a larger border around the text.
The Outer Gap box specifies the amount of space between callout text and the callout line.
The Size box specifies the size of the balloon for Circle, Box (balloon), Boxed Circle, and Triangle callout styles.
The Segment Style buttons let you select one-, two-, or three-segment callout lines.
The Halo Width option determines the amount of blank space that will surround the callout line. This makes it easier to see callouts when they are over objects.
