How long will it take for the company to send its work in Vietnam back to China?

The time for the company to send Vietnam back to China depends on the company's arrangement. If it is a labor service contract, there are provisions on it. Some can return to China after the expiration of the contract, and some will specify the specific time to return to China. If you are hired by a foreign company to work abroad, the other party will directly issue a work visa invitation letter. Some countries can make multiple round trips and come back on holidays.