A Qualified Electronic Signature (QES) system configured to exchange data with first processing means of the requester configured to allow a requester to generate requests requesting a qualified electronic signature through said system to a recipient. The system comprises second processing means of the recipient configured to allow the recipient of the request to sign with his qualified electronic signature. Said second processing means comprise a mobile processing terminal for qualified electronic signature of mobile type, adapted to receive request messages at least on a wireless network able to address said messages, through proximity or remote communications, on the basis of at least one terminal identifier of said mobile processing terminal to said user recipient; said second processing means are adapted to send qualified electronic signature at least on a wireless network suitable for proximity or remote communications in order to verify the signature of the recipient through said system and perform the request.