Are there any paper requirements for printing the application form and writing the application letter when applying for a patent?

(Patent application) Paper used for various documents should be flexible, strong, durable, smooth, matte, and white. Its quality should be equivalent to or higher than 80g offset paper. The specifications (paper for instructions...and other forms) should be 297mm*210mm (A4)

See Chapter 1 of Part 5 of the "Examination Guidelines"