Text Box Shape
When you create a Text Box object, in the Text Box form, you can click the Customise... button to open the Text Box Shape form. Here you can set the properties of the Box and the Text it contains.
Anchor
Select this check box to define an anchor point for a speech bubble or callout. East, North and Z coordinates define the point that remains stationary while the speech bubble is resized or rotated.
Speech Bubble
Select the Speech Bubble option to create a text box in the shape of a speech bubble(i.e. with a triangular anchor).
You can specify the Size of the speech bubble anchor using the slider.
If you click OK with the Speech Bubble settings configured, a preview of the text box is displayed in the Text Box form.
Click Customise... to return to the Text Box Shape form.
Callout
Select the Callout option to apply a Callout style to the anchor point rather than a speech bubble:
Rounded Corners
Select the Rounded Corners check box to apply rounded corners to the shape. Use the slider to adjust the radius of the corners.