1.Foreigners' work permits and work visas have different functions:
1.外国人工作许可证和工作签证的功能不同：
Foreigner work permit refers to the work permit obtained by a person who enters the country with a non work visa in order to obtain the right to work from the government. Except for the licensed work, he can not carry out other work; Work visa: unrestricted, can work normally in this country.
外国人工作许可证指以非工作签证入国的人，为了获得工作的权利向政府部分申请得到的工作准许证，除了经过许可的工作，不能进行其他工作；工作签证：不受限制，可以在此国正常工作。
2. Foreigners' work permits and work visas contain different things:
2.外国人工作许可证和工作签证的含有的东西不同：
A foreigner's work visa includes the date and place of issuance, passport or other international travel document number; Work visa includes visa type, holder's name, gender, date of birth, entry times, entry validity period, stay period, etc.
外国人工作签证包括签发日期、地点、护照或者其他国际旅行证件号码；工作签证包括签证种类、持有人姓名、性别、出生日期、入境次数、入境有效期、停留期限等。
3. The process of applying for a foreigner's work permit and work visa is different:
3.外国人工作许可证和工作签证的申请的过程不一样：
If a foreigner's work permit is an invitation letter issued by a unit or individual in China, the applicant shall provide it in accordance with the requirements of the visa authority stationed abroad; Units or individuals that need to issue invitation letters for work visas shall be responsible for the authenticity of the invitation contents. The visa issued by the port visa authority is valid for one-time entry, and the period of stay indicated in the visa shall not exceed 30 days.
外国人工作许可证是需要提供中国境内的单位或者个人出具的邀请函件的，申请人应当按照驻外签证机关的要求提供；工作签证需要出具邀请函件的单位或者个人应当对邀请内容的真实性负责。口岸签证机关签发的签证一次入境有效，签证注明的停留期限不得超过三十日。
In addition, the conditions for foreigners to apply for work permits and work visas are as follows:
此外，外国人工作许可证和工作签证办理条件：
According to the regulations on the administration of foreigners' employment in China
根据《外国人在中国就业管理规定》
Article 6: the posts employed by foreigners by the employing unit shall be those with special needs, suitable candidates are temporarily unavailable in China, and do not violate the relevant provisions of the state.
第六条： 用人单位聘用外国人从事的岗位应是有特殊需要，国内暂缺适当人选，且不违反国家有关规定的岗位。
Article 7: foreigners must meet the following conditions for employment in China:
第七条：外国人在中国就业须具备下列条件：
1. At least 18 years old, in good health;
1.年满18周岁，身体健康；
2. Have the professional skills and corresponding work experience necessary for their work;
2.具有从事其工作所必须的专业技能和相应的工作经历；
3. No criminal record;
3.无犯罪记录；
4. There is a definite employing unit;
4.有确定的聘用单位；
5. Hold a valid passport or other international documents that can replace the passport.
5.持有有效护照或能代替护照的其他国际证件。
参考资料来源：百度百科-中国工作签证，百度百科-工作许可制度，中国领事服务馆-外国人在中国就业管理规定