Without visa you have no way to come in.
You can get visa at the Chinese Embassy or at Chinese Consulates.
If you come on a business-trip, you usually are asked to present an invitation by a Chinese company.
If you plan to work in China (e.g. service-mechanic working there on a plant for several weeks), then you have to give detailed information about the work you pan to do , where, when etc.
For tourist-visa I don´t know.
Kind regards,
Concerned