Both "Everyone has their job" and "Everyone has their jobs" are grammatically correct, and they can be used in slightly different contexts. "Everyone has their job" suggests that each person has a specific role or responsibility, and it's often used when talking about a single job or task that each person is responsible for. In this case, "their" is a gender-neutral pronoun that can be used to refer to individuals without specifying gender. It's a common and inclusive way to phrase the sentence. "Everyone has their jobs" suggests that each person has multiple jobs or responsibilities. In this context, "jobs" is plural, indicating that each person is responsible for more than one task. It could be used in situations where individuals have a variety of roles or assignments. Using "his/her" instead of "their" is also grammatically correct and can be more specific in terms of gender, but it may sound less inclusive or less natural in some contexts. It depends on the context and the level of gender specificity you want. If you know that everyone in the group is of the same gender, you can use "his" or "her" accordingly. However, if the group is mixed or you want to be inclusive of all genders, "their" is a good choice. So, in summary: "Everyone has their job" is gender-neutral and inclusive. "Everyone has their jobs" implies multiple tasks or responsibilities for each person. "Everyone has his/her job" is specific to gender but can be used when appropriate for the context.