Comodo offers a free certificate management utility for Apache and IIS webservers which helps you quickly generate a CSR then configure and install your certificate.
The first part of enrolling for your SSL
Certificate is to generate a Certificate Signing Request (CSR).
CSR generation is wholly dependent on the software you use on your
web server. Select your web server software from the list after reading
the following general points:
Our SSL Certificates are compatible with almost all popular web server software. If your web server software does not appear on the list, please contact firstname.lastname@example.org with full details of your web server software and we will contact you with further instructions.