We can convert an SSL Certificate to a .pfx file for Windows server.
Requirement: WHM /Terminal access.
Login to WHM panel, and open Terminal:
1) Store your private key file to the /backup directory.
Paste your private key script in the file, then save and close the file.
2) Store your certificate file to the /backup directory.
Paste your cert script in the file, then save and close the file.
3) Store your intermediate file to the /backup directory.
Paste your intermediate CAbundle script in the file, then save and close the file.
4) Export the PFX file to a user domain’s public_html path, so that you can easily download from there.
openssl pkcs12 -export -out /home/cpaneluser/public_html/sslcert.pfx -inkey /backup/private.key -in /backup/certificate.crt -certfile /backup/cabundle.crt
Provide a password two times here, you will need this password when importing the PFX file to an Windows system
5) Go to the cpaneluser’s File Manager, and download the PFX file.