Sometimes it can seem like your employer has much more power than you do. It can be hard to stand up to them if you don’t like something they’re doing, or to ask them for better working conditions. This is where being part of a union can be helpful. One individual employee might seem replaceable and not very powerful, but most businesses can’t run without employees, so when lots of employees join together in unions, they can have a lot more power over what happens to employees.
The point of a union is to negotiate with employers to get better employment conditions for their members. They can also help you out if you’re being treated unfairly or having a disagreement with your employer.