Today , concern about how to create any invoice with only tax amount.
In real business sometimes its needed to create invoice where there is no any products but only vat or any tax.
Ex. Suppose in shipping company which contain an invoice line relating to import VAT. That means that the VAT amount is not a fixed percentage of the invoice.
So, how we can enter supplier invoice ?
Here are some steps that may be useful to you.
1. Set up Tax through(Accounting > Configuration > Tax).
And in it just set tax type to "Python code"
And set as follow(in result just assign price_unit direct no need to multiply).
# price_unit # product: product.product object or None # partner: res.partner object or None result = price_unit
# price_unit # product: product.product object or False result = price_unit