Get-ProvisioningTemplate.ps1

$siteUrl = "https://vinrotlab.io/"
$provisioningTemplateFileName = "startpage.xml"
$pageFileName = "welcome.aspx"
$librarySitePages = "SitePages"
$exportPath = "C:\export"

$provisioningTemplateFilePath = $exportPath + "/" + $provisioningTemplateFileName

function Get-Page($fileName) {
    $pageFile = "/" + $librarySitePages + "/" + $fileName

    # Temp file
    $filePath = $exportPath + "\" + $fileName
    
    # Export files to the folder
    $sitePageFolder = $exportPath + "\" + $librarySitePages
        
    If(!(test-path $exportPath)){
        New-Item -ItemType Directory -Force -Path $exportPath
    }

    If(!(test-path $sitePageFolder)){
        New-Item -ItemType Directory -Force -Path $sitePageFolder
    }
    
    #Save file to locale
    Get-PnPFile -Url $pageFile -AsFile -Path $exportPath -Force
    
    #Copy ..avoid the message '...because it is being used by another process'
    Copy-Item $filePath -Destination $sitePageFolder
    $copyFile = $sitePageFolder + "\" + $fileName
    
    #Add file data to provisioning template
    Add-PnPFileToProvisioningTemplate -Path $provisioningTemplateFilePath -Source $copyFile -Folder $librarySitePages
}