A domani in una mail

Here's a possible translation:

"A domani" is Italian for "tomorrow".

So, if you want to say "see you tomorrow" in a mail, you could write:

"A domani, arrivederci!"

Which translates to:

"See you tomorrow!"

Or, if you want to be more formal, you could write:

"A domani, spero di vederti presto!"

Which translates to:

"See you tomorrow, I hope to see you soon!"

Let me know if you need any further assistance!