This guide will show you how to export an outlook pst file from Outlook 2010. (This is also the same procedure for Outlook versions 2010+)
4. Select Outlook Data File (.pst) and then click on Next.
5. Select the top-most folder, check the box Include subfolders and then click on Next.
6. Be sure to check the option for Do not export duplicate items. Click on the Browse button.
7. Decide where you will export the .pst file and then click OK.
8. Click on Finish.
9. A password box will pop up. Leave all fields blank and just click on OK. (If you create a password and forget this there is no way to recover this password. We recommend leaving this blank.)
Additional information: http://support.sherweb.com/Faqs/Show/how-to-export-an-outlook-2010-pst-file-exchange-2010