When does the registration take effect?
In a normal situation, the registration will take effect from the first day of the calendar quarter following that in which the taxable person informs the Member State of identification that it wishes to start using the scheme.
However, there may be situations in which the taxable person starts making supplies under the scheme before this date. If this is the case, the scheme will start from the date of that first supply, provided the taxable person has informed the Member State of identification that it has commenced activities under the scheme by the tenth day of the month following that first supply. This deadline also applies to any amendment to the registration details where the taxable person has already informed the Member State of identification that it wishes to start from the beginning of the next quarter, but actually starts making supplies before that date. If the taxable person fails to meet this deadline, it is required to register and account for the VAT in the Member State(s) where his customer is located.

How to register for the MOSS in the member state of identification?
The registration is possible only electronically, through the applications you can find at the following links:

Will the Union scheme taxable person be allocated an individual VAT identification number?
No. Under the Union scheme the individual VAT registration number is the same as that which is already allocated to the taxable person by the Member State of identification for domestic supplies. A taxable person cannot register for the Union Scheme without this number.

Will the taxable persons already allocated with national credentials for access to e-services receive a confirmation e-mail from Agenzia delle Entrate with new identification codes or pin codes or passwords?
For national businesses already allocated with the national credentials for access to e-services, no further confirmation e-mail from the Agenzia is needed, because the holding credentials are still valid.

How to register to the MOSS for Non-Union Scheme?
A non-european taxable person that choose to identify in Italy require the registration filling out the online form available on the Agenzia delle Entrate website, on the free access area.
Received the credentials for access to e-services from the Agenzia, the identification number and the VAT number, it logins on “Fisconline” area and changes the password to obtain the second part of the PIN code. With the credential it can fill out the online format at the link “Registration”.

In what currency is the mini One Stop Shop VAT return to be made out?
The VAT MOSS return should be made out in Euro, although Member States of identification which have not adopted the Euro may require the MOSS return to be made out in their national currency. However, when they transfer the return information to the other Member States, the amount will be converted into Euros using the exchange rate as published by the European Central Bank on the last day of the reporting period.