SharePoint Online: Download a File from Library using PowerShell

Requirement: Download a File from SharePoint Online using PowerShell

How to Download File from SharePoint Online Library?
To download a file from library, follow these steps:

• Sign-in to SharePoint Online site >> Navigate to the library where your desired file is located
• Right click on the file and select "Download" option from the context menu.
  
• This gets you the "Save" prompt and the file gets saved in your client machine's Downloads directory.
• In Modern Libraries, You can simply select the file(s) or folder and hit "Download" button from the toolbar.
  

Now, How to download a file from SharePoint Online using PowerShell?

SharePoint Online PowerShell to Download File from Library
Let's download documents from SharePoint Online document library using PowerShell. This PowerShell script downloads file from the SharePoint Online document library (or any library!)

#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 Download-FileFromLibrary()
{ 
    param
    (
        [Parameter(Mandatory=$true)] [string] $SiteURL,
        [Parameter(Mandatory=$true)] [string] $SourceFile,
        [Parameter(Mandatory=$true)] [string] $TargetFile
    )

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

        #Setup the context
        $Ctx = New-Object Microsoft.SharePoint.Client.ClientContext($SiteURL)
        $Ctx.Credentials = $Credentials
    
        #sharepoint online powershell download file from library
        $FileInfo = [Microsoft.SharePoint.Client.File]::OpenBinaryDirect($Ctx,$SourceFile)
        $WriteStream = [System.IO.File]::Open($TargetFile,[System.IO.FileMode]::Create)
        $FileInfo.Stream.CopyTo($WriteStream)
        $WriteStream.Close()

        Write-host -f Green "File '$SourceFile' Downloaded to '$TargetFile' Successfully!" $_.Exception.Message
  }
    Catch {
        write-host -f Red "Error Downloading File!" $_.Exception.Message
    }
}

#Set parameter values
$SiteURL="https://crescent.sharepoint.com/sites/sales/"
$SourceFile="/sites/Sales/Shared Documents/Crescent Legal App Requirements.docx"  #Relative URL 
$TargetFile="C:\Temp\LegalDoc.docx"

#Call the function to download file 
Download-FileFromLibrary -SiteURL $SiteURL -SourceFile $SourceFile -TargetFile $TargetFile 

To download all files from a SharePoint Online document library, use this script: SharePoint Online download multiple files using PowerShell

Download a File from SharePoint Online using PnP PowerShell 
Here is the PnP PowerShell to download a file from SharePoint Online

#Config Variables
$SiteURL = "https://crescenttech.sharepoint.com/sites/marketing"
$FileRelativeURL = "/sites/Marketing/Shared Documents/Discloser Asia.docx"
$DownloadPath ="C:\Temp"

#Get Credentials to connect
$Cred = Get-Credential

Try {
    #Connect to PNP Online
    Connect-PnPOnline -Url $SiteURL -Credentials $Cred
    
    #powershell download file from sharepoint online
    Get-PnPFile -Url $FileRelativeURL -Path $DownloadPath -AsFile
}
catch {
    write-host "Error: $($_.Exception.Message)" -foregroundcolor Red
}

To download a folder from SharePoint Online using PowerShell, use: PowerShell to Download Folder from SharePoint Online