In China, work files are often shared on a work group chat, especially in the desktop version of WeChat. It is also very common to conduct business online with Chinese partners and clients via WeChat, in the same way that we might use Skype.
The reason behind this? The email adoption rate in China is not high. According to China Network Information Center, only 44% of Chinese internet users use an email application. The Chinese have found their own way to use the messaging platform.