In the EU, filing an invention application is primarily done through the European Patent Office (EPO). Inventors can submit a European patent application to protect their invention in multiple EU member states. The application must include a detailed description, claims defining the invention, and any necessary drawings. Once filed, the application undergoes examination to ensure it meets patentability criteria: novelty, inventive step, and industrial applicability. If granted, the patent typically lasts for 20 years, subject to annual renewal fees. Properly documenting the invention process is crucial for protection.