The Stack 
and Unstack commands 
change single-line text to multiline text, and conversely, multiline text to a single line of text. The commands are available when you edit a single-part horizontal or straight annotation feature with the Annotation tool 
and right-click the map.
Stacking is based on spaces, typically between words. Each time you apply the stack command, one or more words are moved to a new line. You can keep stacking annotation text until each word appears on its own line.
Note:
Stack and unstack commands are not available with curved annotation or multipart annotation features.
To stack or unstack a single-part annotation feature, complete the following steps:
- Open a map containing the feature layer you are editing or add the layer to the map.
Tip:
Before editing features, specify which layers can be edited, confirm that the coordinate system assigned to the active map is suitable for the type of edits you're performing, and enable the snap agents that allow you to work effectively.
For a basic checklist of settings, see Configure settings for editing.
- Click the ribbon Edit tab and click Modify
in the Features group.The Modify Features pane appears.
- Expand Alignment, or type Anno in the Search text box and click the Annotation tool .
The tool opens and the Select annotation tool
is automatically active. - To prevent unintended rotation or scaling, uncheck the Enable rotate and resize check box.
- Select the annotation feature to be edited.
Tip:
If you select more than one feature, reselect the feature. Alternatively, click the feature in the pane selection view to flash it in the map, right-click, and click Only Select This
. A selection boundary appears around the selected annotation feature.
- Right-click and choose one of the following commands:
Stack
Move words in the text string to a new line.
Unstack
Move all words on multiple lines to a single line of text.
- Click Finish
or press F2 to finish your edits.