Working with Markups > Annotations > Callouts > To Insert a User-defined Callout
  
To Insert a User-defined Callout
1. In the figure window, select one or more parts, and then click Annotations > User Defined.
* 
Alternatively, click Annotations > User Defined, and then select one or more parts.
The ITM Label dialog box opens with the selected part, or parts listed.
2. Type a name or number the item. For multiple items, press the up and down arrows to move through the ITM Label list.
* 
You can also press ENTER to move through the ITM Label list.
The name or number appears dynamically on the label and in the Item List.
3. Click OK.