Every tenant has a lease that can be enforced in court even if there is nothing in writing.
However, it is probably in your best interest to get every promise by the landlord in writing. Then if there is any question about what promises were made, the written lease can be used as proof. Remember to read and understand the lease completely before you sign it. Whether or not you get the lease in writing is a matter of choice. The advantage of a written lease is that you have proof of your specific agreement, and it makes clear the duties of you and your landlord.