Formal:
* Española: This is the most common and formal way to refer to a woman from Spain. It literally means "Spanish woman."
* Señora: This is a polite and respectful way to address any woman, regardless of her nationality, but can be used when you don't know her name.
Informal:
* Chica: This means "girl" and can be used informally when referring to a young woman.
* Mujer: This is the general word for "woman" and can be used informally.
Other:
* Madrileña: If the woman is from Madrid, you can call her "Madrileña" (woman from Madrid).
* Andaluza: If she is from Andalusia, you can call her "Andaluza" (woman from Andalusia).
The best choice will depend on the specific situation and your relationship with the woman.