I downloaded the certificate of the wikipedia website. Then I executed
openssl x509 -text -in star.wikipedia.org.crt -inform PEM
and it prints out a lot of stuff. Below I think you can find the relevant pieces of information:
kai@MYHOST:~$ openssl x509 -text -in star.wikipedia.org.crt -inform PEM
Version: 3 (0x2)
Signature Algorithm: sha256WithRSAEncryption
Issuer: C=BE, O=GlobalSign nv-sa, CN=GlobalSign Organization Validation CA - SHA256 - G2
Not Before: Dec 10 23:22:05 2015 GMT
Not After : Dec 10 22:46:04 2016 GMT
====> Subject: C=US, ST=California, L=San Francisco, O=Wikimedia Foundation, Inc., CN=*.wikipedia.org
Subject Public Key Info:
Public Key Algorithm: id-ecPublicKey
Public-Key: (256 bit)
ASN1 OID: prime256v1
X509v3 Key Usage: critical
Digital Signature, Key Encipherment
X509v3 Certificate Policies:
X509v3 Subject Alternative Name:
I have marked the relevant section. It says basically
Country = US
State = California
Location = San Francisco
Organization = Wikimedia Foundation, Inc.
You can do the same with your old certificate and then you know exactly what you need to enter in the CSR.
The purpose of this is to provide an identity description the CA can vouch for. The format to describe the identity is taken from the X.500 directory standard which uses those C, L, OU, etc. tokens.
It's probably a good idea to enter the same values from the previous certificate. In case company name or location has changed and you want to reflect that in the X.500 name then your CA will probably start some kind of process to verify that the new name is accurate...