Every student, employee or guest of TUM gets a mailbox automatically. After creation the address is by default TUM-Kennung@mytum.de, e.g. firstname.lastname@example.org.
How to set a TUM e-mail-address:
Please note: TUM, especially the TUMonline System sends important notifications to this address. So it is of your very own interest to check this mailbox regularly or to forward these emails to another mailbox.