Most tenant rights start with a written notice the landlord actually received. Pick the letter, enter your state and the facts, and print a letter you can send by certified mail today.
Break-Lease Letter ($12). Written notice that you are ending the lease early, and why. It gives your move-out date, asks the landlord to re-rent the unit and arrange an inspection, and asks for your deposit back at your forwarding address. It has wording for military orders (the federal SCRA), domestic violence, sexual assault or stalking, failure to repair, and an agreed early end. For the notice rules in your state, see the notice period calculator.
Repair Demand Letter ($15). Formal written notice of the conditions that need repair, citing your state's repair-duty law, with a repair-by date. Written notice is usually the step every other remedy depends on. The letter deliberately does not threaten to withhold rent or deduct repair costs. Those remedies have strict procedures, and getting one wrong can be treated as not paying rent. The guidance delivered with the letter explains what your state allows and the risks.