Gender-neutral language is a way of speaking and writing that doesn't make assumptions about someone's gender. We mainly use this language to avoid excluding people who don't identify with traditional gender roles. For example, the traditional "he" or "she" pronouns only refer to people who identify as male or female.
Using gender-neutral language can mean using non-binary pronouns like "they/them" or using gender-neutral terms such as "they" instead of "he" or "she", or "parent" instead of "mom" or "dad". It also means using terms that refer to both men and women together, like "humans" instead of "mankind".
Some people might be surprised by gender-neutral language at first, but it's actually a really easy change to make, and it makes sure that everyone, regardless of their gender identity, feels included and respected.