This article will show you how to export a single folder from an entire mailbox to a PST file on Exchange Server 2010, 2013 and 2016.
To start the process open EMS and type the command below (change mailbox and source folder path).
New-MailboxExportRequest -mailbox adminu -SourceRootFolder "Inbox/folder" -filepath \\exchange\C$\Source\adminu.pst
You can import it to another mailbox by running the cmdlet below:
New-mailboximportrequest –mailbox mia –filepath \\file\c$\data\admin.pst -targetrootfolder inbox/test"