To Create a Copy of a Text Style

Select Text Styles (Drawing > Annotate > Text dialog launcher).
The Text Styles dialog opens.
Select the desired source text style from the list.
Do one of the following:

From the menu bar of the Text Styles dialog, choose Style > Copy.

or
From the icon bar, click Copy.

A new "Copy of…" style appears in the Text Styles list.
Enter the desired name for the new text style.
Press <Enter>.
The new text style name appears in the Text Styles list.
(Optional) Use the tabs on the Text Styles dialog to change the text attributes as desired.
The Advanced Tab contains all of the settings from the General, Spacing, Under/Overline and Background tabs, as well as some additional less common options.
Do one of the following:

Select Style > Save from the menu bar.

or
From the icon bar, click Save.

Note: The new text style is not automatically activated; you must activate it before it is used for text placement.