SharePoint Online: Copy Files Between Site Collections using PowerShell

Requirement: SharePoint Online Copy Files between Site Collections in document libraries.

PowerShell to Copy Files between Site Collections in SharePoint Online:
Lets copy a single from source to destination.

#Load SharePoint CSOM Assemblies
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.dll"
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.Runtime.dll"

#Set parameter values
$SourceSiteURL="https://crescent.sharePoint.com/sites/sales"
$TargetSiteURL="https://abraaj.sharepoint.com/sites/Ops/"

#Set Source and Destination File URLs - Relative path
$SourceFileURL="/Sites/Sales/Project Documents/Active Users.xlsx"
$TargetFileURL="/Sites/Ops/Shared Documents/Active Users.xlsx"

#Setup Credentials to connect
$Cred= Get-Credential
$Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($Cred.Username, $Cred.Password)

#Setup the contexts
$SourceCtx = New-Object Microsoft.SharePoint.Client.ClientContext($SourceSiteURL)
$SourceCtx.Credentials = $Credentials
$TargetCtx = New-Object Microsoft.SharePoint.Client.ClientContext($TargetSiteURL)
$TargetCtx.Credentials = $Credentials

#Get the Source File
$FileInfo = [Microsoft.SharePoint.Client.File]::OpenBinaryDirect($SourceCtx, $SourceFileURL)

#Copy File to the Target location
[Microsoft.SharePoint.Client.File]::SaveBinaryDirect($TargetCtx, $TargetFileURL, $FileInfo.Stream,$True)

This script simply copies a particular file from source site/site collection to the target site/site collection.

Copy All Files and Folder from One Library to Another Library between different Site Collections:

#Load SharePoint CSOM Assemblies
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.dll"
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.Runtime.dll"

Function Copy-Files
{
  param
    (
        [Parameter(Mandatory=$true)] [Microsoft.SharePoint.Client.Folder] $SourceFolder,
        [Parameter(Mandatory=$true)] [Microsoft.SharePoint.Client.Folder] $TargetFolder
    )
    Try {
        #Get all Files from the source folder
        $SourceFilesColl = $SourceFolder.Files
        $SourceFolder.Context.Load($SourceFilesColl)
        $SourceFolder.Context.ExecuteQuery()

        #Iterate through each file and copy
        Foreach($SourceFile in $SourceFilesColl)
        {
            #Get the source file
            $FileInfo = [Microsoft.SharePoint.Client.File]::OpenBinaryDirect($SourceFolder.Context, $SourceFile.ServerRelativeUrl)

            #Copy File to the Target location
            $TargetFileURL = $TargetFolder.ServerRelativeUrl+"/"+$SourceFile.Name
            [Microsoft.SharePoint.Client.File]::SaveBinaryDirect($TargetFolder.Context, $TargetFileURL, $FileInfo.Stream,$True)

            Write-host -f Green "Copied File '$($SourceFile.ServerRelativeUrl)' to '$TargetFileURL'"
        }

        #Process Sub Folders
        $SubFolders = $SourceFolder.Folders
        $SourceFolder.Context.Load($SubFolders)
        $SourceFolder.Context.ExecuteQuery()
        Foreach($SubFolder in $SubFolders)
        {
            If($SubFolder.Name -ne "Forms")
            {
                #Prepare Target Folder
                $TargetFolderURL = $SubFolder.ServerRelativeUrl -replace $SourceLibrary.RootFolder.ServerRelativeUrl, $TargetLibrary.RootFolder.ServerRelativeUrl
                Try {
                        $Folder=$TargetFolder.Context.web.GetFolderByServerRelativeUrl($TargetFolderURL)
                        $TargetFolder.Context.load($Folder)
                        $TargetFolder.Context.ExecuteQuery()
                    }
                catch {
                        #Create Folder
                        if(!$Folder.Exists)
                        {
                            $TargetFolderURL
                            $Folder=$TargetFolder.Context.web.Folders.Add($TargetFolderURL)
                            $TargetFolder.Context.Load($Folder)
                            $TargetFolder.Context.ExecuteQuery()
                            Write-host "Folder Added:"$SubFolder.Name -f Yellow
                        }
                    }
                #Call the function recursively
                Copy-Files -SourceFolder $SubFolder -TargetFolder $Folder
            }
        } 
    }
    Catch {
        write-host -f Red "Error Copying File!" $_.Exception.Message
    } 
}

#Set Parameter values
$SourceSiteURL="https://crescent.sharePoint.com/sites/sales"
$TargetSiteURL="https://crescent.sharepoint.com/sites/ops"

$SourceLibraryName="Project Documents"
$TargetLibraryName="Documents"

#Setup Credentials to connect
$Cred= Get-Credential
$Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($Cred.Username, $Cred.Password)

#Setup the contexts
$SourceCtx = New-Object Microsoft.SharePoint.Client.ClientContext($SourceSiteURL)
$SourceCtx.Credentials = $Credentials
$TargetCtx = New-Object Microsoft.SharePoint.Client.ClientContext($TargetSiteURL)
$TargetCtx.Credentials = $Credentials

#Get the source library and Target Libraries
$SourceLibrary = $SourceCtx.Web.Lists.GetByTitle($SourceLibraryName)
$SourceCtx.Load($SourceLibrary)
$SourceCtx.Load($SourceLibrary.RootFolder)

$TargetLibrary = $TargetCtx.Web.Lists.GetByTitle($TargetLibraryName)
$TargetCtx.Load($TargetLibrary)
$TargetCtx.Load($TargetLibrary.RootFolder)
$TargetCtx.ExecuteQuery()

#Call the function 
Copy-Files -SourceFolder $SourceLibrary.RootFolder -TargetFolder $TargetLibrary.RootFolder 

Copy All Files from One Library to Another Library along with Metadata values:
This script copies all files and folders between document libraries in different site collections, preserving metadata field values such as: Created by, Modified By, Created At, Modified At, etc.

#Load SharePoint CSOM Assemblies
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.dll"
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.Runtime.dll"

Function Copy-AllFilesWithMetadata
{
  param
    (
        [Parameter(Mandatory=$true)] [Microsoft.SharePoint.Client.Folder] $SourceFolder,
        [Parameter(Mandatory=$true)] [Microsoft.SharePoint.Client.Folder] $TargetFolder
    )
    Try {
        #Get all Files from the source folder
        $SourceFilesColl = $SourceFolder.Files
        $SourceFolder.Context.Load($SourceFilesColl)
        $SourceFolder.Context.ExecuteQuery()

        #Iterate through each file and copy
        Foreach($SourceFile in $SourceFilesColl)
        {
            #Get the source file
            $FileInfo = [Microsoft.SharePoint.Client.File]::OpenBinaryDirect($SourceFolder.Context, $SourceFile.ServerRelativeUrl)

            #Copy File to the Target location
            $TargetFileURL = $TargetFolder.ServerRelativeUrl+"/"+$SourceFile.Name
            [Microsoft.SharePoint.Client.File]::SaveBinaryDirect($TargetFolder.Context, $TargetFileURL, $FileInfo.Stream,$True)

            #Copy Metadata field values
            $SourceListItem = $SourceFile.ListItemAllFields
            $SourceFolder.Context.Load($SourceListItem)
            $SourceFolder.Context.ExecuteQuery()

            #Get the new file created
            $TargetFile = $TargetFolder.Context.Web.GetFileByServerRelativeUrl($TargetFileURL)
            $TargetListItem = $TargetFile.ListItemAllFields

            #Set Metadata values from the source
            $Author =$TargetFolder.Context.web.EnsureUser($SourceListItem["Author"].Email)
            $TargetListItem["Author"] = $Author
            $Editor =$TargetFolder.Context.web.EnsureUser($SourceListItem["Editor"].Email)
            $TargetListItem["Editor"] = $Editor
            $TargetListItem["Created"] = $SourceListItem["Created"]
            $TargetListItem["Modified"] = $SourceListItem["Modified"]
            $TargetListItem.Update()
            $TargetFolder.Context.ExecuteQuery()

            Write-host -f Green "Copied File '$($SourceFile.ServerRelativeUrl)' to '$TargetFileURL'"
        }

        #Process Sub Folders
        $SubFolders = $SourceFolder.Folders
        $SourceFolder.Context.Load($SubFolders)
        $SourceFolder.Context.ExecuteQuery()
        Foreach($SubFolder in $SubFolders)
        {
            If($SubFolder.Name -ne "Forms")
            {
                #Prepare Target Folder
                $TargetFolderURL = $SubFolder.ServerRelativeUrl -replace $SourceLibrary.RootFolder.ServerRelativeUrl, $TargetLibrary.RootFolder.ServerRelativeUrl
                Try {
                        $Folder=$TargetFolder.Context.web.GetFolderByServerRelativeUrl($TargetFolderURL)
                        $TargetFolder.Context.load($Folder)
                        $TargetFolder.Context.ExecuteQuery()
                    }
                catch {
                        #Create Folder
                        if(!$Folder.Exists)
                        {
                            $TargetFolderURL
                            $Folder=$TargetFolder.Context.web.Folders.Add($TargetFolderURL)
                            $TargetFolder.Context.Load($Folder)
                            $TargetFolder.Context.ExecuteQuery()
                            Write-host "Folder Added:"$SubFolder.Name -f Yellow
                        }
                    }
                #Call the function recursively
                Copy-AllFilesWithMetadata -SourceFolder $SubFolder -TargetFolder $Folder
            }
        } 
    }
    Catch {
        write-host -f Red "Error Copying File!" $_.Exception.Message
    } 
}

#Set Parameter values
$SourceSiteURL="https://crescent.sharepoint.com/sites/sales"
$TargetSiteURL="https://crescent.sharepoint.com/sites/Ops"

$SourceLibraryName="Project Documents"
$TargetLibraryName="Documents"

#Setup Credentials to connect
$Cred= Get-Credential
$Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($Cred.Username, $Cred.Password)

#Setup the contexts
$SourceCtx = New-Object Microsoft.SharePoint.Client.ClientContext($SourceSiteURL)
$SourceCtx.Credentials = $Credentials
$TargetCtx = New-Object Microsoft.SharePoint.Client.ClientContext($TargetSiteURL)
$TargetCtx.Credentials = $Credentials

#Get the source library and Target Libraries
$SourceLibrary = $SourceCtx.Web.Lists.GetByTitle($SourceLibraryName)
$SourceCtx.Load($SourceLibrary)
$SourceCtx.Load($SourceLibrary.RootFolder)

$TargetLibrary = $TargetCtx.Web.Lists.GetByTitle($TargetLibraryName)
$TargetCtx.Load($TargetLibrary)
$TargetCtx.Load($TargetLibrary.RootFolder)
$TargetCtx.ExecuteQuery()

#Call the function 
Copy-AllFilesWithMetadata -SourceFolder $SourceLibrary.RootFolder -TargetFolder $TargetLibrary.RootFolder