Add description in Swagger for optional parameters in request body

I would like to add a description in Swagger documentation that some parameters in request body are optional.

Should I use @ApiParam annotation for such description ? I tried to use @ApiModelProperty(notes = "") but it didnt work.

@PostMapping(value = "/users/")
public ResponseEntity<Object> users(@RequestBody PostUserRequest postUserRequest) {}

@Data
@AllArgsConstructor
@NoArgsConstructor
@Builder
public class PostUserRequest {
    @ApiParam(value = "This is optional parameter")
    private String phone;
}