Lease and confirmation from the landlord
When you conclude a rental agreement with your landlord you will receive your own original hardcopy of the lease signed by the landlord.
For the official registration of your home address (for a stay in Germany of three months or longer) you also need a confirmation from the landlord for presentation to the registration office (in German: Wohnungsgeberbestätigung zur Vorlage bei der Meldebehörde). This is an official form of the Free State of Saxony. You can download it from this official website:
It must be filled in by your landlord. You will need it to register at the Bürgerbüro (see there).