If you can write a case yourself, you can download the patent application form from China National Intellectual Property Administration online and fill in this form according to its example. Except where it is signed, it is in the form of a request for a patent for invention or utility model, an abstract of the specification, drawings, claims, specifications and drawings. If the fee is reduced, you must pay the fee reduction request. These forms were downloaded from China National Intellectual Property Administration's website.
If there is anything you don't understand, you can also go to the patent agency in this province to inquire. The phone number is also on China National Intellectual Property Administration's website. You can call for advice.