As there has been a bit of talk about archiving lately and the new Archive Folder vs the Online Archive in Office365 https://support.office.com/en-us/article/Archive-in-Outlook-2016-for-Windows-25f75777-3cdc-4c77-9783-5929c7b47028?ui=en-US&rs=en-US&ad=US and https://www.petri.com/exchange-online-archive-options .I'd though I'd do a post about the Archive Item operation in EWS which was introduced in Exchange 2013 and is an interesting lever for admins to use if they want to look a manually archiving items to a Mailboxes online archive without using Archive Policies. The Archive Item operation is basically designed to allow you to move items from the Primary to the Online Archive more easily instead of having to batch a Move operation. To use this operation you need to enumerate the Items you want to archive (using a search filter or other restriction) and then provide that as one of the inputs for archive Items as longs as the folder where the Items are being archived from. The only real catch I've found when using it is that you need to use Impersonation or the Automated folder creation in the Archive doesn't seem to happen.
I've created a script that allows you to query a Mailbox folder using an AQS query based on the item received date and then invoke the Archive Items operation on those items and put this up on GitHub here https://github.com/gscales/Powershell-Scripts/blob/master/ArchiveItems.ps1
This script requires EWS impersonation https://msdn.microsoft.com/en-us/library/office/dn722376(v=exchg.150).aspx to run
To run the script you pass in the Mailbox you want to run the script against, the FolderPath where the Items exist that you want to archive and the Date of the Items you want to archive from. Eg to archive items older then one year you would run
Invoke-ArchiveItems -MailboxName firstname.lastname@example.org -FolderPath "\Clutter" -queryTime (Get-Date).AddDays(-365)