we are 4 persons and prepare to visit in Shenzhen ,expo ISLE 2020 , please inform the docs required?

1. Basic Requirements
(1) Passport with at least six months of remaining validity and blank visa pages
(2) Photocopy of the passport
(3) A completed Visa Application Form with one passport-size photo
(4) Photocopy of previous Chinese visa(s) if any

2. Supporting Documents
(1) Documents on the commercial activity issued by a trade partner in China, or trade fair invitation or other invitation letters issued by relevant entity or individual

For first-time applicants, also need:
(2) Recommendation letter from the sending Nepali company
(3) Company registration & PAN registration
(4) Personal or company bank statement of the last three months