1. First off, you need to ensure that you have root access. Otherwise, please contact the webhosting/server administrator.
2. Log into the SSH.
3. Run the following command and replace the domain_name with your domain name such as sectigo.com,

# openssl pkcs12 -export -out /backup/domain_name.pfx -inkey /etc/ssl/private/domain_name.key -in /etc/ssl/certs/domain_name.crt