Hello Molly, There are a few ways to express 'same to you'. The shortest is 'igualmente'. Por ejemplo: - ¡Feliz Año nuevo! - ¡Igualmente! This can be applied to any conversation. Depending on the sentence you state first, you can also use other expressions. If you happen to wish a good day, someone may reply 'a ti también' (to you too) or 'ten un buen día tú también' (have a good day you too). Anyway, I would recommend to use 'igualmente' since this is the most versatile.

- igualmente - lo mismo te digo

You too