Use your mobile phone to pick up peppers, register for free, then click on the link to apply for a certificate and key, enter the necessary information, and it will tell you what time it will be available to download (about 5 or 6 It will be ready in an hour, and the completed certificate will have 17 permissions). Then you can search for the "Free Signature" software based on your model in Paojiao, download and install it (it is very small), and then wait for the certificate and key. After it is done, download it (compressed file in zip format, just unzip it to a place you can find it!), run "Free Signature", and go to Options--Settings--"Signature Certificate" and "Signature Key" respectively. Just select the prepared certificate (cer format) and (key format)! "Free Signature" is easy to use, and you will definitely be using it yourself soon.