#powershell to get sharepoint online site permissions
Function Generate-SPOSitePermissionRpt($SiteURL,$ReportFile)
{
    Try {
        #Get 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
  
        #Get the Web
        $Web = $Ctx.Web
        $Ctx.Load($Web)
        $Ctx.ExecuteQuery()
  
        #Write CSV- TAB Separated File) Header
        "URL `t Object `t Title `t Account `t PermissionType `t Permissions" | out-file $ReportFile
  
        Write-host -f Yellow "Getting Site Collection Administrators..."
        #Get Site Collection Administrators
        $SiteUsers= $Ctx.Web.SiteUsers
        $Ctx.Load($SiteUsers)
        $Ctx.ExecuteQuery()
        $SiteAdmins = $SiteUsers | Where { $_.IsSiteAdmin -eq $true}
  
        ForEach($Admin in $SiteAdmins)
        {
            #Send the Data to report file
            "$($Web.URL) `t Site Collection `t $($Web.Title)`t $($Admin.Title) `t Site Collection Administrator `t  Site Collection Administrator" | Out-File $ReportFile -Append
        }
  
        #Function to Get Permissions of All List Items of a given List
        Function Get-SPOListItemsPermission([Microsoft.SharePoint.Client.List]$List)
        {
            Write-host -f Yellow "`t `t Getting Permissions of List Items in the List:"$List.Title
 
            $Query = New-Object Microsoft.SharePoint.Client.CamlQuery
            $Query.ViewXml = "<View Scope='RecursiveAll'><Query><OrderBy><FieldRef Name='ID' Ascending='TRUE'/></OrderBy></Query><RowLimit Paged='TRUE'>$BatchSize</RowLimit></View>"
 
            $Counter = 0
            #Batch process list items - to mitigate list threshold issue on larger lists
            Do { 
                #Get items from the list
                $ListItems = $List.GetItems($Query)
                $Ctx.Load($ListItems)
                $Ctx.ExecuteQuery()
           
                $Query.ListItemCollectionPosition = $ListItems.ListItemCollectionPosition
  
                #Loop through each List item
                ForEach($ListItem in $ListItems)
                {
                    $ListItem.Retrieve("HasUniqueRoleAssignments")
                    $Ctx.ExecuteQuery()
                    If($ListItem.HasUniqueRoleAssignments -eq $True)
                    {
                        #Call the function to generate Permission report
                        Get-Permissions -Object $ListItem
                    }
                    $Counter++
                    Write-Progress -PercentComplete ($Counter / ($List.ItemCount) * 100) -Activity "Processing Items $Counter of $($List.ItemCount)" -Status "Searching Unique Permissions in List Items of '$($List.Title)'"
                }
            } While ($Query.ListItemCollectionPosition -ne $null)
        }
  
        #Function to Get Permissions of all lists from the web
        Function Get-SPOListPermission([Microsoft.SharePoint.Client.Web]$Web)
        {
            #Get All Lists from the web
            $Lists = $Web.Lists
            $Ctx.Load($Lists)
            $Ctx.ExecuteQuery()
  
            #Get all lists from the web  
            ForEach($List in $Lists)
            {
                #Exclude System Lists
                If($List.Hidden -eq $False)
                {
                    #Get List Items Permissions
                    Get-SPOListItemsPermission $List
  
                    #Get the Lists with Unique permission
                    $List.Retrieve("HasUniqueRoleAssignments")
                    $Ctx.ExecuteQuery()
  
                    If( $List.HasUniqueRoleAssignments -eq $True)
                    {
                        #Call the function to check permissions
                        Get-Permissions -Object $List
                    }
                }
            }
        }
  
        #Function to Get Webs's Permissions from given URL
        Function Get-SPOWebPermission([Microsoft.SharePoint.Client.Web]$Web)
        {
            #Get all immediate subsites of the site
            $Ctx.Load($web.Webs) 
            $Ctx.executeQuery()
   
            #Call the function to Get Lists of the web
            Write-host -f Yellow "Getting the Permissions of Web "$Web.URL"..."
  
            #Check if the Web has unique permissions
            $Web.Retrieve("HasUniqueRoleAssignments")
            $Ctx.ExecuteQuery()
  
            #Get the Web's Permissions
            If($web.HasUniqueRoleAssignments -eq $true)
            {
                Get-Permissions -Object $Web
            }
  
            #Scan Lists with Unique Permissions
            Write-host -f Yellow "`t Getting the Permissions of Lists and Libraries in "$Web.URL"..."
            Get-SPOListPermission($Web)
   
            #Iterate through each subsite in the current web
            Foreach ($Subweb in $web.Webs)
            {
                 #Call the function recursively                           
                 Get-SPOWebPermission($SubWeb)
            }
        }
  
        #Call the function with RootWeb to get site collection permissions
        Get-SPOWebPermission $Web
  
        Write-host -f Green "Site Permission Report Generated Successfully!"
     }
    Catch {
        write-host -f Red "Error Generating Site Permission Report!" $_.Exception.Message
   }
}
  
#Set parameter values
$SiteURL="https://domain.sharepoint.com/sites/xyzax-version1"
$ReportFile="C:\SitePermissionReport.csv"
$BatchSize = 500
  
#Call the function
Generate-SPOSitePermissionRpt -SiteURL $SiteURL -ReportFile $ReportFile