What you're asking how to tell them is just the tip of the iceberg. There is only one way to report it: by words through your mouth, because it is not good to notify your parents by text or letter. You are a grown woman and have every right to structure your personal life however you want. It seems that the "iceberg" has a large part under water - you have not completed the process of psychological separation from your parents. In order to complete it, go to a psychologist for counselling, because you are still in the position of a child, and this can hinder you from building a future life. Sometimes it happens that you are separated territorially and financially but not mentally. You have a lot of resources to deal with this situation. It will be easier for you if you solve this problem before marriage, so that you won't start your marriage with guilt and your happiness won't be overshadowed by negative feelings towards your parents and yourself in connection with it. Congratulations on finding a life partner and getting married. It is a beautiful event and an important time. Work on your relationship with your parents and all will be well!