Is this necessary to create the purchase invoice when we have already added the opening quantity for the products?

If you have added opening quantity for the product and again you are creating purchase invoice using the same products, the products quantity will be duplicated in your inventory.

To avoid the duplication of product quantity you can remove the opening quantity mentioned in the product details.

To remove opening quantity you can follow below steps.

Step 1: Go to “Products and Services” and click on “Edit”.

Step 2: Remove the Opening Quantity and Update the Item.