If you send a greeting card, you could write something like this:
"Dear Truc
Wishing you happiness, good health and wealth for the New Year.
All the best,
Michelle"
But if you send a text message or message on social media to many friends and family, you could say something like:
"Happy New Year one and all, wishing you all the best fortune and happiness!"
Or you could very simply say "season's greetings!"
There are many things you could say. I hope these ideas help :)