"¿Cómo estás hoy?"
Translation:How are you today?
Literally, this says "How you-are today?". The verb tells us that the subject is "you" even thouh the "tu" is missing (as is normal in Spanish). So here, as so often, the verb is the big clue as to the meaning.
To translate your version, the verb would need to be "esta" ir "it is".