When a customer is creating or renewing a DRM certificate, they have to follow the guidelines outlined in the DRM Certificate Enrollment guide.
https://helpx.adobe.com/content/dam/help/en/primetime/drm/drm_certificate_enrollment.pdf
- Details on how to generate a new Certificate Signing Request (CSR) can be found on Page 7
- Details on how to submit the Certificate and CSR request can also be found on Page 7
- Converting the certificate to PFX and PEM/DER files can be found on Page 9