You can get the contacts of the China emabssy in Malaysia on this wesite:
https://www.travelchinaguide.com/embassy/malaysia.htm
You must come to the visa office of the Embassy or Consulate -General where you reside to submit the application; or If you cannot come personally, you may send someone else or a travel/visa agent to come to the visa office of the Embassy or Consulate-General where you reside for application processes.
Mail applications are not acceptable and will be refused.