Is there alternate approach to adding new field to json

Getting Help Code Review
1

https://play.golang.org/p/548a20mPSoR

import (
	"encoding/json"
	"fmt"
	"log"
	"os/exec"
	"strings"
)
type Company struct {
	ID struct {
		Oid string `json:"$oid"`
	} `json:"_id"`
	Name string `json:"name"`
	Pin  string `json:"Pin"`
}
func (c Company) MarshalJSON() ([]byte, error) {
	uuid, _ := exec.Command("uuidgen").Output()
	uuid0 := strings.ReplaceAll(string(uuid),"\n","")
	le := len(strings.Split(c.Name, " "))
	conc := c.Name[:5] + " " + c.Pin[:5]
	n := struct {
		Name  string `json:"name"`
		Pin   string `json:"pin"`
		Pid   string `json:"pid"`
		Words int	 `josn:"words"`
		Dummy string `json:"dummy"`
	}{
		Name:  c.Name,
		Pin:   c.Pin,
		Pid:   uuid0,
		Words: le,
		Dummy: conc,
	}
	ans, error:= json.Marshal(n)
	if error !=nil {
		log.Fatal(error)
	}
	return ans, error
}


func main() {
	data := []byte(`[{"_id": {"$oid": "585cbb871"}, "name": "Pqr Mn", "pin": "U2334"}, {"_id": {"$oid": "305a6776912"}, "name": "Abc Xyz", "pin": "U12345"}, {"_id": {"$oid": "5a704ed1b"}, "name": "Lbs Ll", "pin": "U34567"}]`)
	c := []Company{}
	error := json.Unmarshal(data,&c)
	if error != nil{
		log.Fatal(error)
	}
	out, _ := json.Marshal(c)
	fmt.Println(string(out))

}```