A landlord can demand a deposit from you as a renter. This is a one time fee given to the landlord during your stay at the accommodation. It is to cover any costs that could occur during your stay. When the lease has expired, and the housing left in an acceptable state, the deposit is returned.
If you want to know more about if you have to pay a deposit, we recommend you to ask the landlord in question what requirements there are when moving it.