I am working on E-Comm portal for selling Electrical products. As soon as order placed, can Quick books raise Auto Invoice?

Thanks for choosing QuickBooks, arunsivasamy-hot.

For now, you'll have to manually create the invoice as soon as the customers place the orders. However, QuickBooks has a feature that'll let you create estimates for the products, then convert to invoices. Please check this article for more information: Convert An Estimate Into An Invoice In QuickBooks Online.

For your reference, please read this article to know how to record payments in QuickBooks to mark open invoices as paid: Record Invoice Payments In QuickBooks Online.

Don't hesitate to keep in touch if you have any other concerns.