Add-Type -Path "c:folderMicrosoft.SharePoint.Client.dll"

Add-Type -Path "c:folderMicrosoft.SharePoint.Client.Runtime.dll"

$siteUrl = “https://mytenant.sharepoint.com/sites/mysitecollection”

$username = "admin@mytenant.onmicrosoft.com"

$password = Read-Host -Prompt "Enter password" -AsSecureString

$ctx = New-Object Microsoft.SharePoint.Client.ClientContext($siteUrl)

$credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($username, $password)

$ctx.Credentials = $credentials

$webCreationInformation = New-Object Microsoft.SharePoint.Client.WebCreationInformation

$webCreationInformation.Url = "site1"

$webCreationInformation.Title = "Site 1"

$webCreationInformation.WebTemplate = "STS#0"

$newWeb = $ctx.Web.Webs.Add($webCreationInformation)

$ctx.Load($newWeb)

$ctx.ExecuteQuery()

$newWeb

Write-Host "Title" $newWeb.Title

Connect-SPOService -Url https://contoso-admin.sharepoint.com -credential admin@contoso.com

New-SPOSite [-Url] <UrlCmdletPipeBind> -Owner <String> -StorageQuota <Int64> [-CompatibilityLevel <Int32>] [-LocaleId <UInt32>] [-NoWait <SwitchParameter>] [-ResourceQuota <Double>] [-Template <String>] [-TimeZoneId <Int32>] [-Title <String>]