What to expect in a job offer

It all depends. You were not clear, so there are some assumptions that need to be made.

[1] You are not Chinese.
[2] You are expecting an offer from a Chinese company in China.
[3] You have a degree, and thus can obtain expert status through the employer.

This is what you can expect...

[1] A salary.
[2] A contract.
[3] Reimbursement of transportation costs.
[4] Chinese holidays off.

The contract will be tied to your visa. So you will need to go through the Chinese government pre-screening routine to verify that you are qualified to work in China. The contract will determine the duration of your stay, and tied to that will be a return ticket back to the USA. That is a Chinese government requirement.

Depending on your skill level, position, and situation, as well as the needs of the employer, the following can be negotiated BEFORE an offer is made.

[1] Housing allowance.
[2] Health Insurance.

IF you are negotiating with a non-Chinese company for a position inside of China, you might be able to negotiate the following...

[1] Educational assistance for your children.
[2] Relocation costs for furniture.

I would advise you to stop thinking too much. If an offer will be made, then you can read the offer and make your decisions. Other than that, you are counting your eggs before you buy any chickens.

Happy year of the pig. Best regards.