Log in into the Admin Section and click on User Profile tab on the top menu.
You will see a search bar.
Look for the user you need to send a Welcome email to using the search module.
Click/select the user for which you would like to send a welcome email. A dialogue box will open.
In the User profile dialogue box, scroll down. You will see an option called “Send Welcome email”
Simply click on the button “ Send Welcome Email” and the email will be sent out to this user.
Please note that it has to be done one by one, user by user.