Is there a way that I can input all the raw materials then converted into finished product with keeping the inflow and outflow of inventory ?

It looks like you're referring to an inventory assembly feature, Jhongsyee-gmail-.

The option is available on the Desktop versions only. You can only set up and track inventory items in QuickBooks Online.

For more information, feel free to refer to this article: Set up and track your inventory in QuickBooks Online.

If you have other concerns, please don't hesitate to let us know. We're just one post away. Keep safe!

@jhongsyee-gmail- 

QBO doesn't provide any assembly feature. Consider having a manufacturing app to integrate with your QBO account.