The self-employed person's invoice consists of a tax base, VAT and income tax withholding.
For the first three years, the self-employed person can choose to have 7% on the invoice. By the fourth year, you must retain a 21%.

The self-employed can make fractional payments for 20% of our benefits quarterly. We can also discount the deductions or not deduct them. For this the model 130 is used.
That is, we calculate the income minus expenses, by 20%. That amount is entered into the Treasury and then deducted as a payment on account in the declaration.
It shows a case of how is the bill of a freelance who charges 40 euros an hour, 8 hours a day and has worked 20 days. (8x20x40)