The free text annotation is made of one or several text lines added on a document’s page.
To add a Free text:
In the Annotation pane:
Select Free text in the drop-down list of Annotation types
Click on the page where you want the free text to be displayed. The text is laid out in a rectangular box. Click again inside the box to make the keyboard blinking cursor appear.
Type in your text. The box height automatically
adapts to fit the required space. You can adapt the box width when
the cursor shows a horizontal
resize icon
You
can move the position of your free text when it is selected and the
move cursor appears 
Edition options:
Text Font size
Text color (and border and connecting line if selected): quick color selection or advanced color selection

Text alignment: left, center or right
Text border
Connecting line. When Connecting
line is selected, a small 'tail' is attached to the text box.
The end point of that line can be moved where you want on the page
(thanks to the move cursor
). When the end point
is moved, the start point location is updated automatically to prevent
from the connecting line to be drawn over the annotation text.

Default features of a Free text:
The text is drawn on a semi-transparent white background. That way it is easier to read without masking completely the content behind.
The text font style predefined.
The connecting line has the same width as the border line.
For more general information on annotation mode, see chapter Using_Annotations.