Enabling auto-sending of SMS & Email to customer on New Sales:

1. First, setup the Email SMTP and/or SMS details in Business settings.
2. Go to Notification Template
3. Under Customer Notification you will see New Sales notification.
4. There you will find the option to enable  Auto Send Email  &  Auto Send SMS, enable it and save.
5. Now when ever you make a sales a Email or SMS notification will be send to customer.

Important NOTE:

1. If there is any error in Email or SMS configuration then sales will not get submitted, so test it properly.
2. Email notification will only get send in case the customer have a valid email present
3. Similarly SMS will only get send if the mobile number is present.