Add and Remove Site Collection Administrator across Tenant through Powershell.

    <#
******-------------------------------------------------------------------------------------------------******
Author          -> Shiv Mangal Singh
Date            -> 12 th March - 2017
Description     -> Add and Remove Site Collection Administrator across Tenant through Powershell.

******-------------------------------------------------------------------------------------------------******
 #>
    Import-Module Microsoft.Online.SharePoint.PowerShell -DisableNameChecking
    $Credential = Get-Credential
    #Variables for processing
    $AdminURL = "https://Office365.contoso.com/"
    $loginName ="shivsingh@contoso.com"
    #Connect to SharePoint Online
    Connect-SPOService -Url $AdminURL -Credential $Credential
    # Get All Site Collection Name
    $Sitecolls = Get-SPOSite -Limit All
    foreach($Site in $Sitecolls)
    {
    Write-Host "Adding Site Collection Administrator for Site:" $Site.url
    #Add Site collection Admin
        Set-SPOUser -Site $Site -LoginName $loginName -IsSiteCollectionAdmin $True
    # Remove Site Collection admin
    # Set-SPOUser -Site $Site -LoginName $loginName -IsSiteCollectionAdmin $False
    }

 # Disconnect to SharePoint Online
 Disconnect-SPOService