What is the plural form of woman?

The plural form of "woman" is "women".

It's a good question because this is an irregular plural. You don't simply add an ‘s’. The pronunciation also changes quite a bit, which is important to note. "Woman" is pronounced with a 'woo' sound. However, "women" is pronounced with a short 'i' sound, like 'wim-in'. It is a common point of confusion for many learners, so you are not alone in asking this.