Origin Certificate with multiple domains

[fritex]

SSL for multiple domain

An Origin certificate will only cover the domain under which it was issued. If you want to create a certificate for another domain, you’ll have to do this in the context of that domain. You can’t have one certificate covering two different domains.

Share/combine cloudflare origin CA certificate for multiple domains

You just have a second certificate issued for the second domain and configure this in your web server just like you did with the first. Nothing to combine there, they are two separate certificates and they need to be configured separately.