SharePoint Online: How to Create a Site Collection using PowerShell?

Requirement: Create a new site collection in SharePoint Online using PowerShell!

How to Create a Site Collection in SharePoint Online?
Site collection in SharePoint is a logical group sites with a common top-level site and subsites organized as a hierarchy. Every site collection share common top site, navigation, security, content types, etc. To create a SharePoint Online Site collection from Browser, follow these steps:

• Login to New SharePoint Admin Center as a tenant admin or SharePoint Online Administrator. 
• Click on Sites >> Active Sites from left navigation >> Click on "Create" >> and then "Private Site collection" to create a new site collection.
• Pick either "Team Site" option to create a modern team site collection with Office 365 group or "Other Options" to create a modern team site without Office 365 group.
  
• Pick the site template such as "Team site", Provide the site Name, URL, Administrator options and click on "Finish" to create a site collection in SharePoint Online.
  

Wait for a moment and your site collection should appear in the site collections list. Now, let's see how to create a site collection in SharePoint Online using PowerShell.

SharePoint Online: PowerShell to Create Site Collection
To create site collections in SharePoint Online using PowerShell, Use: New-SPOSite cmdlet. Here is an example:

#Connect to SharePoint Online
$Credential = Get-credential 
Connect-SPOService -url https://crescent-admin.sharepoint.com -Credential $Credential

#sharepoint online new site collection powershell
New-SPOSite -Url https://crescent.sharepoint.com/sites/marketing -Owner salaudeen@crescent.com -StorageQuota 1000 -Title "Marketing Team Site" -Template STS#0 

Wait for a minute and this creates a new site collection in SharePoint online.

SharePoint Online: Create Modern Team Site Collection using PowerShell:
Similarly, you can create a modern site collection in SharePoint Online by specifying the site template as "STS#3". E.g.

#Connect to SharePoint Online
Connect-SPOService -url "https://crescenttech-admin.sharepoint.com" -Credential (Get-credential)
 
#Create a modern team site
New-SPOSite -Url "https://crescenttech.sharepoint.com/sites/Purchase" -Owner "Salaudeen@TheCrescentTech.com" -StorageQuota 2048 -Title "Purchase Team Site" -Template "STS#3"

Now, lets add some error handling, and wrap it inside a re-usable function:

Create SharePoint Online Site Collection using PowerShell:
Lets add some error handling and make the script bit more flexible for SharePoint Online to create site collection with PowerShell. 

#powershell to create site collection sharepoint online
Function Create-SPOSite 
{
  param
    (
        [string]$Title  = $(throw "Please Provide the Site Title!"),
        [string]$URL = $(throw "Please Provide the Site URL!"),
        [string]$Owner = $(throw "Please Provide the Site Owner!"),
        [int]$StorageQuota = $(throw "Please Provide the Site Storage Quota!"),
        [int]$ResourceQuota = $(throw "Please Provide the Site Resource Quota!"),
        [string]$Template = $(throw "Please Provide the Site Template!")
    )

#Connection parameters 
$AdminURL = "https://Crescent-admin.sharepoint.com"
$AdminName = "SpAdmin@Crescent.com"
$AdminPassword="Password Goes here"
$SecurePassword = $AdminPassword | ConvertTo-SecureString -AsPlainText -Force 
$Credentials = New-Object -TypeName System.Management.Automation.PSCredential -argumentlist $AdminName, $SecurePassword
 
Try{
    #Connect to Office 365
    Connect-SPOService -Url $AdminURL -Credential $Credentials
 
    #Check if the site collection exists already
    $SiteExists = Get-SPOSite | where {$_.url -eq $URL}
    #Check if site exists in the recycle bin
    $SiteExistsInRecycleBin = Get-SPODeletedSite | where {$_.url -eq $URL}

    If($SiteExists -ne $null)
    {
        write-host "Site $($url) exists already!" -foregroundcolor red
    }
    elseIf($SiteExistsInRecycleBin -ne $null)
    {
        write-host "Site $($url) exists in the recycle bin!" -foregroundcolor red
    }
    else
    {
        #sharepoint online create site collection powershell
        New-SPOSite -Url $URL -title $Title -Owner $Owner -StorageQuota $StorageQuota -NoWait -ResourceQuota $ResourceQuota -Template $Template
        write-host "Site Collection $($url) Created Successfully!" -foregroundcolor Green
    }
}
catch {
    write-host "Error: $($_.Exception.Message)" -foregroundcolor Red
    }
}

#Parameters to create new site collection
$SiteTitle = "Demo"
$SiteURL= "https://Crescent.sharepoint.com/sites/demos"
$SiteOwner = "spsadmin@Crescent.com"
$StorageQuota = 1000
$ResourceQuota = 300
$SiteTemplate = "STS#0"

#Call The function to create site collection
Create-SPOSite -Title $SiteTitle -URL $SiteURL -Owner $SiteOwner -StorageQuota $StorageQuota -ResourceQuota $ResourceQuota -Template $SiteTemplate 

Now the new site collection will be created in a minute! You can verify by going to SharePoint Online Admin Center.

PowerShell to Create New Site Collection in SharePoint Online using CSOM
Here is the SharePoint Online PowerShell to Create New Site Collection

#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"
Add-Type -Path "C:\Program Files\SharePoint Online Management Shell\Microsoft.Online.SharePoint.PowerShell\Microsoft.Online.SharePoint.Client.Tenant.dll"
 
#Set Parameters
$AdminCenterURL = "https://Crescenttech-admin.sharepoint.com/"
$NewSiteURL = "https://Crescenttech.sharepoint.com/Sites/HR"

Try {
    #Setup Credentials to connect
    $Cred= Get-Credential
    $Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($Cred.Username, $Cred.Password)
     
    #Setup the Context
    $Ctx = New-Object Microsoft.SharePoint.Client.ClientContext($AdminCenterURL)
    $Ctx.Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($Cred.Username, $Cred.Password)
  
    #Get the tenant object 
    $Tenant = New-Object Microsoft.Online.SharePoint.TenantAdministration.Tenant($Ctx)

    Write-Host -f Yellow "Creating site collection..."
    #Set the Site Creation Properties
    $SiteCreationProperties = New-Object Microsoft.Online.SharePoint.TenantAdministration.SiteCreationProperties
    $SiteCreationProperties.Url = $NewSiteURL
    $SiteCreationProperties.Template =  "STS#0"
    $SiteCreationProperties.Owner = "salaudeen@theCrescenttech.com"
    $SiteCreationProperties.StorageMaximumLevel = 1000
    $SiteCreationProperties.UserCodeMaximumLevel = 300
 
    #powershell script to create site collection in sharepoint online
    $Tenant.CreateSite($SiteCreationProperties) | Out-Null
    $ctx.ExecuteQuery()
 
    #Create the site in the tennancy
    write-host "Site Collection Created Successfully!" -foregroundcolor Green
}
catch {
    write-host "Error: $($_.Exception.Message)" -foregroundcolor Red
}

To create multiple SharePoint Online site collections in bulk from a CSV file, refer: SharePoint Online: Create Multiple Site Collections in Bulk from a CSV File using PowerShell

SharePoint Online: PnP PowerShell to Create Site Collection
Here is how to create site collection using PnP PowerShell in SharePoint Online

#Define Variables
$AdminCenterURL = "https://crescenttech-Admin.sharepoint.com"
$SiteURL = "https://crescenttech.sharepoint.com/sites/procurement2"
$SiteTitle = "Crescent Procurement Portal"
$SiteOwner = "Salaudeen@TheCrescentTech.com"
$Template = "STS#3" #Modern Team Site
$Timezone = 4

#Get Credentials to connect
$Cred = Get-Credential

Try
{
    #Connect to Tenant Admin
    Connect-PnPOnline -URL $AdminCenterURL -Credential $Cred
    
    #Check if site exists already
    $Site = Get-PnPTenantSite | Where {$_.Url -eq $SiteURL}

    If ($Site -eq $null)
    {
        #sharepoint online pnp powershell create site collection
        New-PnPTenantSite -Url $SiteURL -Owner $SiteOwner -Title $SiteTitle -Template $Template -TimeZone $TimeZone -RemoveDeletedSite
        write-host "Site Collection $($SiteURL) Created Successfully!" -foregroundcolor Green
    }
    else
    {
        write-host "Site $($SiteURL) exists already!" -foregroundcolor Yellow
    }
}
catch {
    write-host "Error: $($_.Exception.Message)" -foregroundcolor Red
}

You can also use New-PnPSite cmdelet to create Modern Team sites and communication sites.