2. In your case, payment can be made through non-trade forms;
3. This company in China may not have been contacted. Let them ask SAFE, if there is such service trade payment, you should sign a service agreement, explaining the reason, amount, payment method and so on.
4. For domestic service trade, the tax of 10% will be withheld, or you can provide proof that this income has been declared and paid to the local tax authorities abroad. If this country has a tax treaty with China, it can be exempted from tax in China.