NVivo is a qualitative data analysis (QDA) computer software package produced by QSR International. NVivo helps qualitative researchers to organize, analyze and find insights in unstructured or qualitative data like interviews, open-ended survey responses, journal articles, social media and web content, where deep levels of analysis on small or large volumes of data are required [Wikipedia]. This article demonstrates how to export codebook on NVivo.
A codebook in qualitative or mixed methods research is an authoritative description of how research data is analyzed for a particular project [Scalar].
To export a codebook, go to the Share ribbon and select ‘Export Codebook’:

You can choose where you want to save the Codebook (click on Browser) then click OK.

A word document will automatically open containing your codebook.

If you have many codes and want to categorize them visually by printing the codes, see how to print codes using a Codebook in NVivo. It is useful for Thematic Analysis or Grounded Theory Methodology for the axial coding stage to be able to physically group your nodes.