The Digital Twin is defined as a simulation model that represents the true physical product to a sufficient extent, considering its purpose, during the entire service life of the product. In this context, the simulation model also includes the real-world loading and supports, obtained from testing. Test data is also used to validate and update a simulation model so that structural responses can be estimated with confidence even at locations that will not be instrumented.Validation and updating of finite element models is best approached in a systematic way. The workflow includes data management, test planning, correlation analysis, sensitivity analysis,model updating and post-processing the results. It can be done as soon as a prototype is available but also during service life to ensure the simulation model remains accurate.Therefore this technology will become an important factor in the Digital Twin. Some applications will be presented in areas like material identification, substructuring and structural health monitoring.