A tenant can demand a written lease between the landlord and himself/herself.
Ensure that the tenancy agreement includes information such as the names of parties entering the agreement, their addresses, the address of the property that is to be rented, the rental amount, lease period, whether it's furnished or unfurnished, if electricity and internet is payable by the tenant in addition to the stipulated rent, the notice period (typically three months unless stated otherwise) and so on.
Including an inventory list is an effective way of ensuring that the property contains all the items on the list both when the tenant signs and takes over the property, and again when the tenant hands over the property at the end of the lease.
Here is an example of a standard contract, by Forbrukerrådet