From 1 July 2024, the National e-Invoice System (KSeF) will become a mandatory solution necessary for documenting business transactions. KSeF allows structured invoices in xml format (e-invoices) to be issued and made available. The introduction of compulsory documentation of transactions via KSeF is a major challenge for taxpayers and it is therefore worth starting preparations in advance. First of all, it is necessary to analyse which sales/purchase transactions will be documented via KSeF and which will not be affected by the new obligations. In the next stage, consideration should be given to modifying the existing workflow or introducing completely new solutions. Certainly for those taxpayers already using an electronic document flow in their companies, the implementation of structured invoices will go more smoothly. On the other hand, in the case of accounting offices that use online platforms for communication with their clients, the design and implementation of a document flow using e-invoices will be more efficient, and existing clients will certainly benefit from this. For years, NOBILIS accounting office has been working with an innovative online platform that automates the work of the office, SaldeoSMART.   Mandatory e-invoicing will come into force from 1 July 2024