The sticky note annotation appears as an icon on a document’s page. When single-clicking on the icon, a pop-up window with the text content is shown.
To add a Sticky Note:
In the Annotation pane:
Select Sticky note in the drop-down list of Annotation types
Select a sticky note type in the drop-down list of types
Select a color for the sticky note
Click on the page where you want the sticky note to be shown. The annotation is created. The text content is still empty
Type your text in the text box attached to the icon
You
can move the position of the note when it is selected and the move cursor appears 
Edition options:
Icon Color: quick color selection or advanced color selection

Various sticky note types:
Comment:
with a speech bubble icon ![]()
Key: with a star icon ![]()
Note: with an information symbol icon
![]()
Help: with a help icon ![]()
Insert: with a plus symbol icon ![]()
Question: with a question mark symbol ![]()
Remark
: with an exclamation
mark symbol ![]()

from one of its lower corner.
Note: The text color or text font of a Sticky note cannot be edited. It is not supported by the PDF format.
For more general information on annotation mode, see chapter Using_Annotations.