Hi,

I have configured send as and send on behalf for one user but when he sends mail he gets that mail in his sent box. Is it possible if I send mail as someone else that that person get mail in his sent box becuase I am sending mail as him?

Thank you in advance

You can control this via a Registry setting or via an Exchange option (depending on your Exchange version).
See: Save Sent Items in owners mailbox

Hello,

We have Exchange 2013. Where can I change that, please?

I found this but it is not working in exchange 2013 and I don't know why.

• Get-MailboxSentItemsConfiguration
• Set-MailboxSentItemsConfiguration

When I run it i get this error message 

Get-MailboxSentItemsConfiguration : The term 'Get-MailboxSentItemsConfiguration' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that
 the path is correct and try again.

I found answer. Sent Items configuration will be available in Exchange Server 2013 Cumulative Update 9. Right now it is availabe only for Exchange 2010 SP2 RU4