Search mailbox in Exchange 2013/2016 for keywords, save to a targetMailbox then export PST.

SearchExchangeMailBox.ps1

# Search Mailbox's for given keywords
#
# Make sure the targetMailbox exists, if the folderName folder does not that will be created automatically.
#

#
# Made by Mitchell Urgero
# 
#

# For Exchange 2013/2016
Add-PSSnapin Microsoft.Exchange.Management.PowerShell.SnapIn;

$idents        = ""    # username's of mailboxes you want to search EX: $idents = "user1","user2","user3"
$targetMailbox = ""    # Mailbox where to save results (before export to PST)
$folderName    = ""    # Folder in TargetMailbox to put the results (before export to PST)
$searchTerm    = ""    # search term to use in idents mailbox(s) (same as what you would use in outlook)
$resultPath    = ""    # UNC path to export the PST to

foreach($i in $idents){
    Write-Host "Searching $i"
    search-mailbox -Identity "$i" -searchquery "$searchTerm" -targetmailbox "$targetMailbox" -TargetFolder "$folderName" -loglevel full
}

New-MailboxExportRequest -Mailbox "$targetMailbox" -IncludeFolders "$folderName" -FilePath "$resultPath"