$OU="<yourOU>"
$upnSuffix="@yourdomain"
$database="<database name>"
$firstNamePrefix="Keshav"
$lastNamePrefix="Arora"
$password="password"
$pass =ConvertTo-SecureString $password -AsPlainText -Force
$emlPrefix="emailPrefix_"
$numOfUsers=10
for($i=1;$i -le $numOfUsers;$i++) {
$fn=$firstNamePrefix+$i
$ln=$lastNamePrefix+$i
$alias=$firstNamePrefix+"."+$lastNamePrefix+$i
$displayname= $firstNamePrefix+" "+$lastNamePrefix+" "+$i
Write-Host $i $fn $ln $upnPrefix $displayname
New-Mailbox -Name $alias -Password $pass -UserPrincipalName ($alias + $upnSuffix) -Database $database -OrganizationalUnit $OU -FirstName $fn -Lastname $ln -DisplayName $displayname
$smtpServer="localhost"
$smtp=New-Object Net.Mail.SmtpClient
$smtp.Host="<Your Hub transport Server>"
$to=$emlPrefix+$alias+"@<email domain>"
Write-Host $to
$from="<from address>"
$smtp.Send($from, $to, "My First Email Subject", "Email Body")
}