email timestamp-what does it mean

Hi Maxiems,

Thank you for posting your concern here in Microsoft Community.    

In the standard display mode the time stamp will display the time in your time zone  in the header, the local timezone as defined on the viewing computer.

So basically, emails time-stamp displays the time it was received and in accordance with the time-zone of receiver.

Are you observing an incorrect timestamp while receiving mails on outlook.com email?

Sometimes there are discrepancies if you are using an email client (outlook 2010,2013 etc.) due to some kind of issues on the server end (if you are connected to a domain/server).If you are using outlook.com through browser (not an email client), it should display the correct timestamp as per receiving end. Let us know if it is incorrect. 

Hope this information is helpful. Feel free to get back to us if you have any more questions.