How can I add a new collection with Firebase 9.8.2

methods: {
      registerUser(){
        const auth = getAuth();
        createUserWithEmailAndPassword(auth, this.user.email, this.user.password).then((datauser)=>{
         dbItemAdd.add({
          name: this.user.name,
          email: this.user.email,
          uid: datauser.user.uid,
        })
          router.push({
            name:'home'
          })
        }).catch((error) => {
        console.log(error.code)
        switch (error.code) {
          case "auth/invalid-email":
            this.errMsg = "Invalid email";
            break;
          case "auth/weak-password":
            this.errMsg = "weak password";
            break;
          case "auth/email-already-in-use":
            this.errMsg = "email already in use";
            break;
        }
      })

      }
    },