If you live in the same house as your landlord, you are an ‘excluded occupier’, more commonly known as a ‘lodger’. If you want to move out of your room you will need to give the landlord notice. This is usually a rental period, depending on if you pay your rent monthly or weekly - If you have a written contract, check the terms to see what your notice period is. It is best to give notice in writing (email is fine) to avoid any confusion.
You will need to make sure that you leave your room clean and tidy, and ensure that you have not caused any damage. Your landlord could make deductions from your deposit otherwise. It would be a good idea to take photos of your room as proof of the condition you leave it in on your last day. Your landlord is not obliged to protect your deposit and therefore you may need to negotiate with them in order to get your full deposit back. If your landlord refuses to return your deposit, or you disagree with the amount deducted, you would be able to take County Court action via the Small Claims Court. There are fees associated with this.