If Apple's mobile phone can't sign an electronic signature, you can sign it with a digital signature or try handwriting on the screen. If all else fails, please change your mobile phone.

Mobile phone electronic signature is the general name of modern authentication technology. According to the Uniform Electronic Transactions Act of the United States, "electronic signature" generally refers to "an electronic sound, symbol or program associated or logically associated with an electronic record, and the electronic sound, symbol or program is signed or adopted by someone for the purpose of signing an electronic record".

Electronic signature is not a digital image of written signature, but actually an electronic code, which can be used by the recipient to verify the identity and signature of the sender conveniently on the Internet.