Demonstrateds how to upload a file into SharePoint Online via WebDAV

SPOUploadFile.ps1

Add-Type -Path "c:\Program Files\Common Files\microsoft shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.Runtime.dll"
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\SharePoint Client Components\16.0\Assemblies\Microsoft.Online.SharePoint.Client.Tenant.dll"

function Connect-SPO ([string] $Username, [string]$Password, [string]$Url) {
    
    $Context = New-Object Microsoft.SharePoint.Client.ClientContext($Url)
    $Context.Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($Username, $(ConvertTo-SecureString -AsPlainText $Password -Force))
    $Context.ExecuteQuery()
    
    $AuthenticationCookie = $Context.Credentials.GetAuthenticationCookie($Url, $true)
    $WebSession = New-Object Microsoft.PowerShell.Commands.WebRequestSession
    $WebSession.Credentials = $Context.Credentials
    $WebSession.Cookies.SetCookies($Url, $AuthenticationCookie)
    
    $FormsDigest = $Context.GetFormDigestDirect()
    $WebSession.Headers['X-RequestDigest'] = $FormsDigest.DigestValue
    
    $Context.Dispose()
    return $WebSession
}




#Usage
$WebUrl = "https://contoso.sharepoint.com/"
$Username = "john@contoso.onmicrosoft.com"
$Password = ""
$filePath = "C:\Users\user\Documents\Sample.png"
$FolderUrl = "/Documents"

$FileInfo = New-Object System.IO.FileInfo($filePath)

#Connect
$Session = Connect-SPO -Username $Username -Password $Password -Url $WebUrl
# Upload file
$targetFileUrl = "$WebUrl/documents/$($FileInfo.Name)"
Invoke-WebRequest -Uri $targetFileUrl -Method Put -WebSession $Session -InFile $filePath