IEIM300121 - Country-by-Country reporting: Directions relating to how CbC reports will be filed
The UK rules use many terms and definitions that are taken from the OECD guidance and that guidance should be checked when completing a CbC report.
CbC reports must be filed online through a secure HMRC portal. The MNE will need to register online (once only but this can be amended subsequently), in order to be able to use the online submission portal. The report must be made in the form of an XML document. The reason for this is that XML documents can be validated and provide a common medium for exchange between the countries who have introduced CbC reporting rules.