Formal:
* Я тоже скучаю по вам. (Ya tozhe skuchayu po vam.) - This is the most formal way to say it, literally meaning "I also miss you."
* И я скучаю по вам. (I ya skuchayu po vam.) - This is a more direct translation of "I miss you too," but still formal.
Informal:
* Я тоже скучаю. (Ya tozhe skuchayu.) - This is a more casual way to say "I miss you too," literally meaning "I miss you too."
* Я скучаю по тебе. (Ya skuchayu po tebe.) - This is a more intimate way to say "I miss you too," using the informal "you" (tebe).
* И я скучаю. (I ya skuchayu.) - Similar to the informal "I miss you too" above.
Other options:
* И я скучаю по тебе. (I ya skuchayu po tebe.) - A bit more affectionate than the previous options.
* Я тоже скучаю по тебе. (Ya tozhe skuchayu po tebe.) - A more direct translation of "I miss you too," using the informal "you" (tebe).
The best way to say "I miss you too" in Russian will depend on your relationship with the person you are talking to.