Upload of Network Share to Sharepoint Document Library

I'm not aware of a tool from MS to do this.

There are many 3rd party tools, from vendors like Metalogix, ShareGate and Others

the tricky part is the Security because your on-premises accounts must be mapped to their cloud equivalents.

I have found that many of my clients wanted to do this, but after demonstrating the benefits of multiple document libraries with metadata and views, they changed their mind. A direct file share copy typically prevents the users from realizing many of the benefits of SharePoint.  

This script will give you the highlevel attributes such as Created time and Modified time. Please modify the script with the required attributes. 

You need to create a csv file with columns Sitename (Site url) and UserFolder (Parent folder path). 

Downlaod the file 'uploadfiles.psm1' from the attachment and place it in a folder. Replace the Import-Module path with the path in which the psm1 file was placed and run the script. 

FYI: This script can also be used to copy files to multiple sites by mapping the site urls in the csv. 

#$cred= Get-Credential
$csv = Import-Csv 'C:\csv\users3.csv'
$User = "Admin@tenantname.com"
$Password = "password"


#Add references to SharePoint client assemblies and authenticate to Office 365 site – required for CSOM
Add-Type -Path ([System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint.Client").location)
Add-Type -Path ([System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint.Client.runtime").location)

Import-Module  C:\uploadfiles.psm1

Foreach($Channel in $csv)
{
$SiteURL = $Channel.Sitename 
$Folder = $Channel.UserFolder
$rootfolder=$folder.Replace("\","\\")
$libraryName = "Documents"

#Bind to site collection
$ctx = New-Object Microsoft.SharePoint.Client.ClientContext($SiteURL)
$Creds = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($User,$(convertto-securestring $Password -asplaintext -force))
$ctx.Credentials = $Creds

$Web = $ctx.Web
$ctx.Load($Web)
$ctx.ExecuteQuery()

#Retrieve list
$ParentFolder = $ctx.Web.Lists.GetByTitle($libraryName).RootFolder
$ctx.Load($ParentFolder)
$ctx.ExecuteQuery()

Function UploadFiles($web,$path,$docLibrary)
{


$files = Get-ChildItem $path

foreach ($file in $files) 
{  

   if($file.GetType().Name -eq "DirectoryInfo") 
   {
  $foldername=$file
  $parent=$file.Parent.FullName
  $parent1=$parent+"\"
    If($parent1 -eq $Folder)
  {
  
    $folder = $ParentFolder.Folders.Add($foldername)
    $ParentFolder.Context.Load($folder)
    $ParentFolder.Context.ExecuteQuery()
    $CreationTime= $foldername.CreationTime
    $LastAccessTime=$foldername.LastWriteTime
    $item1 = $folder.ListItemAllFields
  $item1["Modified"] =$LastAccessTime
  $item1["Created"] =$CreationTime 
  $item1.Update()
  $ctx.ExecuteQuery()
  $CreationTime=$null
  $LastAccessTime=$null
   }
   Else
   {
    $Urlpath1= ($parent -split "$rootfolder" )[1]
  $foldernames1=$Urlpath1
  if($foldernames1 -like "*\*")
  {
  $foldername1=$foldernames1.Replace("\","/")
  }
  Else
  {
  $foldername1=$foldernames1
  }
  $ServerRelativeUrlOfRootFolder = $ParentFolder.ServerRelativeUrl
  $uploadFolderUrl=  $ServerRelativeUrlOfRootFolder+"/"+$foldername1
  $targetFolder = $ctx.Web.GetFolderByServerRelativeUrl($uploadFolderUrl)
  $Upload = $targetFolder.Folders.Add($foldername);
  $targetFolder.Context.Load($Upload)
  $targetFolder.Context.ExecuteQuery()
  $CreationTime= $foldername.CreationTime
  $LastAccessTime=$foldername.LastWriteTime
  $item = $Upload.ListItemAllFields
  $item["Modified"] =$LastAccessTime
  $item["Created"] =$CreationTime 
  $item.Update()
  $ctx.ExecuteQuery()
  $CreationTime=$null
  $LastAccessTime=$null


   }
   
    $Folderpath1=$file.FullName
   
    UploadFiles $web $Folderpath1 $docLibrary
   }
   Else
   {
  $filepath= [System.IO.Path]::GetDirectoryName($file.FullName)
  $Urlpath= ($filepath -split "$rootfolder" )[1]
  $foldernames=$Urlpath
  if($foldernames -like "*\*")
  {
  $foldername=$foldernames.Replace("\","/")
  }
  Else
  {
  $foldername=$foldernames
  }   
  $CreationTime= $file.CreationTime
  $LastAccessTime=$file.LastWriteTime

   
$test=UploadFileInSlice -ctx $web -libraryName $docLibrary -foldername $foldername -fileName $File.FullName -CreationTime $CreationTime -LastAccessTime $LastAccessTime
$foldername=$null
  $CreationTime=$null
  $LastAccessTime=$null

}
}

}
UploadFiles -web $ctx -path $Folder -docLibrary $libraryName


}