Follow following steps to send welcome email:
- Select customer in customer selector drop down (first green button in action bar) list.
- Click on gear icon in the first column. This will pop up options box as shown below:

- Click on Edit Customer link. Then at the bottom of Edit Customer window click on Send Login Detail button.
You can use your own custom email as welcome email. To use your own email template, design your email content and forward to your designated project coordinator.