"Buenos días" is how it is normally said, but remember that this is literally "good days" in the plural. You can also say "buen día" and still be correct
Buenos dias = Good day
No es un buen dia = It's not a good day/morning (Spanish does not distinguish between 'good day' and 'good morning')
Good day baby i am good!
buenos días
I am assuming you would like to know how to say "what a Day" in Spanish. That would be Que dia
Buenos días.
A good day
Did you have a good day in Spanish.
Buen día, buenos días
The phrase "buen día" translates to "good day" in English.
No es un buen día.
es un buen dia