How to submit a patent application to the State Patent Office after filling it out?

Just give it to the local patent office. Specific requirements may vary from place to place. It is best to consult directly at the Patent Office. That's what happens when you don't apply for a case through a patent agency. A lot of things have to run by themselves. Generally, every provincial capital city has a patent office. For example, if you are in Hubei, you can check with Wuhan Patent Office. You can consult the materials you need to prepare by telephone first, but the pass rate of cases applied through non-patent agency channels is relatively low.