Hi @tchevalier,
Let's Encrypt doesn't include these fields in any of its certificates, as a matter of policy, because it doesn't have a way to verify automatically that the information provided is correct. The only thing Let's Encrypt can validate is the result of connecting to particular domain names over the Internet, and thereby the certificate requester's apparent control over those names. As a result, that's the only information that Let's Encrypt will include in a certificate.
That means that if you do request these fields in a certificate signing request (CSR) or with other software, they will simply be ignored by Let's Encrypt and not end up in your issued certificate.
If you need these fields to be included in your certificate for some reason, you'll need to get a certificate from a different (paid) certificate authority that can issue certificates in the OV or EV categories. Those include some information about the requester's location and legal identity, which has to be verified offline, not just by automated software.