Learn Spanish (Spain): El médico está en el hospital ahora.

The preposition en is very flexible in Spanish. It is the most common way to express "in", "on", or "at" a location. Depending on the English translation you prefer, en el hospital can mean either "in the hospital" or "at the hospital".

Why do we use está instead of es for the doctor?

We use está (from the verb estar) because we are talking about a physical location. Whenever you want to say where someone or something is located, you always use estar rather than ser.

Do I pronounce the 'h' in hospital like I do in English?

No, the letter 'h' is always completely silent in Spanish. You pronounce the word starting right from the 'o' sound. Also, notice that the speaking emphasis goes on the very last syllable.

How would I say this if the doctor was a woman?

You would change the masculine word el médico to the feminine form, la médica. The rest of the sentence would stay exactly the same.

Could the word ahora go somewhere else in the sentence?