Yeah, lots of people using WeChat everyday. (Actually it's 微信, instead of WeChat. WeChat is English version for foreigners, it's totally different) So technically you can use it to chat with anyone in China. That's the best thing you can do when you learn Chinese. But there have some issues. WeChat tried to develop its business system, so too many people sell merchandice on it. They add you from somewhere, chat with you, finally just try to convince you to buy something. So if you just try to make some Chinese friends on it, you will got disappointed.