Openssl req

openssl req -config root-ca.cnf  -key /your_path/private/root-ca_key.pem -new -x509 -days 3650 -sha256 -extensions v3_ca -out /your_path/private/root-ca_cert.pem

See also

• openssl [ rand | s_client | passwd | openssl req | openssl rsa | openssl genrsa | openssl x509 | openssl ca | openssl verify | openssl ec | openssl dgst | openssl pkcs12 | openssl asn1parse | openssl help | .cer to .pem, openssl version
• OpenSSL: RSA, ECDSA, WolfSSL, AES, Diffie-Hellman (DH) key-exchange, /etc/ssl/openssl.cnf, OpenSSL v3