How to customize oauth2/token request body using spring Authorization server

Question

How to customize Oauth2/token endpoint in Spring-authorization-server for Authorization Code grant type or any?

currently I have not configured any authorization server. so to get the token, its basically straight forward.

existing code sample

//Rest Controller

@RestController
@RequestMapping("api/v1")
public class TokenController{

@PostMapping("/token")
public TokenResponse getToken(@RequestBody TokenRequest tokenRequest){
return tokenService.getToken(tokenRequest);
}
}

@Data
@NoArgsConstructor
@AllArgsConstrucor
@Builder
public class TokenRequest {
  
String grantType;
String CustomerName;
String customerId;

}

As mentioned above, from the tokenRequest, I am getting the customerName, and sessionId and then I am searching for it in the database. once the record is found, I am adding it to the jwt user claim set.And the access token gets generated.

Now i decided to make use of spring's inbuilt Oauth2Authorization server as mentioned in spring doc

openid-configuration shows the token endpoint [oauth2/token] however this endpoint takes only the below in the requestBody

1. grantType
2. redirection_uri
3. code // this is the authorization code which I get in the [oauth2/authorize](oauth2/authorize) call

My question is how can i add, customerName and customerId to this [oauth2/token](/oauth2/token) endpoint ?

are there any references that I can follow ?

in the latest spring boot I do not see @EnableAuthorizationServer