The most common and direct way to say "yes" in Spanish is "sí" (pronounced "see"), which is used in both formal and informal contexts. Besides "sí," there are other ways to say yes depending on the situation, such as:

• Claro (of course)
• Por supuesto (of course)
• Bueno (alright/okay)
• Cómo no (of course, enthusiastic yes)
• De acuerdo (agreed)

These alternatives can add nuance or emphasis depending on the formality or enthusiasm of the response.

So simply saying "sí" covers the general meaning of "yes" in Spanish.