Regarding China work Visa, I am from Bappaditya,India

China work visa is usually with a single entry, valid for 3 months and with no duration of stay (000). You need to apply for a residence permit at local PSB within 30 days after entry. And the residence permit will work as a multiple entry visa, with it you can leave and come back China anytime you need if it is valid. But if you have not get the residence permit and leave with your single entry work visa, you can not come back with it, and a new visa is required. And your wife need also documents from China (as you did for your work visa), your company and official office if she want to accompany you in China.