Internal applications: What you should pay attention to and what mistakes you should avoid. If you're applying internally, you shouldn't feel too confident.
You already know your superior - on the one hand that can be an advantage, but on the other hand it can quickly turn into a disadvantage. For the internal application, you also need a cover letter, as for other applications. You do not need school or university certificates for an internal application. Previous employment references are generally not necessary, Arbeitsrechte.de informs.