WeChat is the most popular mobile app in China. Unlike any other IM app, WeChat is an app which can do a lot of things. If you want to communicate with your clients in China, the best communication tool is WeChat.
Being a remote worker for more than two years, I have learned few things to make it work. If you can find out what your best way to work remotely is. Working remotely will be more productive than working in the office when it comes to creative work.