Excuse me: which is more cost-effective for patent application, paper application or electronic application?

it's safer to use paper, and it doesn't cost much.

Before electronic application, an agreement must be signed with the China Patent Office, and some supporting documents need to be provided in paper, so it is better to apply directly in paper. Paper applications can be made 365 days a year, while electronic applications can only be made during legal working hours on legal working days.