tls – register a X.509 self-signed certificate

I have two parts that need to perform mutual authentication. However, the certificates are self-signed and so the parts must register their certificates each other.

Does anyone know how this procedure can be accomplished?

i am reading this OAuth 2.0 Mutual-TLS Client Authentication and Certificate-Bound Access Tokens where it states

This method of mutual-TLS OAuth client authentication is intended to
support client authentication using self-signed certificates. As a
prerequisite, the client registers its X.509 certificates (using
“jwks” defined in (RFC7591)) or a reference to a trusted source for
its X.509 certificates (using “jwks_uri” from (RFC7591)) with the
authorization server.

So I am following OAuth 2.0 Dynamic Client Registration Protocol where it states

Client’s JSON Web Key Set (RFC7517) document value, which contains
the client’s public keys. The value of this field MUST be a JSON
object containing a valid JWK Set. These keys can be used by
higher-level protocols that use signing or encryption. This
parameter is intended to be used by clients that cannot use the
“jwks_uri” parameter, such as native clients that cannot host
public URLs. The “jwks_uri” and “jwks” parameters MUST NOT both
be present in the same request or response

However I can not find the answer to my question