Creating JWT Files

1 - Install Openssl
2 - Goto C:\Program Files\OpenSSL-Win64\bin
3 - Run as admin openssl.exe
4 - genrsa -out privatekey.pem 1024
5 - req -new -x509 -key privatekey.pem -out publickey.cer -days 36050
6 - Upload .crt certifcate on digital signatures input field on salesforce
7 - Upload .key on base_path of project 

For more info https://mannharleen.github.io/2020-03-03-salesforce-jwt/