Einen schönen 4.(vierten) Juli
Hau'oli la 'eha o Iulai
Assuming you mean "how" to say happy in German, there are a couple of different ways: Froh and gluecklich.
Happy Friday in German is glücklicher Freitag
Juli
happy - glücklich Also fröhlich, froh
I am not a happy puppy is an English idiom and cannot be translated into German in a way that conveys it's meaning.
happy married life = glückliches Eheleben
"Happy Saint Patrick´s Day" in German is: Fröhlichen St. Patricks Tag
Frohes Neues Jahr.
Die glücklichen Kinder.
Multiple reasons; it comes out of the mouth smother, to distinguish between other countries' Independence Days, and it sounds more American.