All invoices must show IVA (VAT) which needs to be added to it, declared and paid!
The law requires that any individual who is going to become an IVA collector must register and the income charges on the invoice also needs to be declared for income tax purposes. Therefore the simple answer is that registration is necessary if you are going to issue invoices.
Some companies online offer the service of issuing invoices on your behalf with no need to register as long as they can show you have a small part of the partnership. This type of companies has recently been under scrutiny by the Social Security inspectors’ dept and some have been closed down as illegal.
On some exceptional circumstances, a person might be able to issue an invoice only by registering with the Tax office and not in the social security as self-employed. Consider the following scenario. The employee of a company who is paying his social security as an employee needs to do an extra job for 1 day: He is invited to give a talk or conduct a seminar. This is not his regular business, and he is already paying Social Security, therefore he only need to register as IVA collector for the occasion and can issue his invoice to the event organiser.
In most cases though registering only at the Tax Office will not work and can result in serious problems as there are other implications not considered in this article. Regretfully, so far, current legislation does not permit the self employed to register for only a few days and to pay social security accordingly. The social security contributions for the self employed, are for a minimum of one complete month with the result that small jobs may not be worth doing especially when the income is to be spent virtually all on social security.
On the bright with the new law for Autonomo workers, already approved and pending to come into force over the following weeks, it is expected that autonomos might be able to sign off and back on again for a maximum of 3 times per year and pay social security only for the time they are on. This way autonomos can sign off paying social security when they may have no work or during holidays.