One Stop Shop (OSS)
The mini One Stop Shop (MOSS), which was put in place on 1 January 2015, has been extended to become a One Stop Shop (OSS) as from 1 July 2021 covering a wider range of supplies and has introduced further simplifications.
This enlarged One Stop Shop covers three special schemes: the non-Union scheme, the Union scheme and the import scheme.
The scope of the already existing non-Union scheme and Union scheme has been extended, whereas the import scheme has been newly introduced. These special schemes allow taxable persons to declare and pay VAT due in Member States in which these taxable persons are (in general) not established via a web-portal in the Member State in which they are identified (Member State of identification). The schemes are optional.
In practice, a taxable person who is registered for an OSS scheme in a Member State (the Member State of identification) will electronically submit OSS VAT returns detailing the supplies that can be declared in the respective OSS scheme along with the VAT due.
The VAT return is submitted quarterly in the non-Union and in the Union scheme and monthly in the import scheme. If a taxable person chooses to use one of the schemes, he has to declare all supplies that fall under that particular scheme via the OSS return of the respective scheme. These OSS VAT returns, along with the VAT paid, are then transmitted by the Member State of identification to the corresponding Member States of consumption via a secure communications network.
The OSS VAT returns are additional and do not replace the VAT return a taxable person submits to his Member State under his domestic VAT obligations. The OSS schemes are available to taxable persons established in the EU and outside the EU. Taxable persons who are established in the EU can use the Union scheme and the import scheme, whereas taxable persons who are not established in the EU can possibly use all three schemes, i.e. the non-Union, the Union and the import scheme. Without the OSS schemes, the supplier would be required to register in each Member State in which he supplies goods or services to his customers.
The OSS schemes are optional for taxable persons. However, when choosing to use an OSS scheme, the taxable person must apply the scheme to all supplies falling under this scheme in all relevant Member States. The taxable person cannot, therefore, opt to use the OSS scheme just for supplies in some Member States and not for supplies in other Member States. Once opting into the scheme, it is applicable for all supplies to consumers in all Member States.
You can find more info in the EU OSS portal One Stop Shop (europa.eu)