what does it mean when a http post request outputs this result: "_id": "627a0a15d6781db12a66f038"?

Question

All i want to do is log the input gotten from the frontend to the console. Im using postman to test the operations. However the results i've been getting are really confusing. I have searched several solutions, but non really helped solve the problem.

so here's the code:

app.use(bodyParser.urlencoded({
    extended: true
  }));

app.use(bodyParser.json());  

app.get("/", (req, res) => {
    res.send ("HomePage");
});

app.post("/add", (req, res) => {

  const newTodo = new Todo(req.body);

  res.send(newTodo);
})

pls note the model Todo was to format the incoming request according to the schema defined in another file.

const mongoose= require("mongoose");

const TodoSchema = new mongoose.Schema({
    todo:{
        type: String,
        required: true,
        trim: true,
        createdAt: Date.now
    },
});

module.exports = new mongoose.model("Todo", TodoSchema);

Here's the Output im getting:

{
    "_id": "627a0a15d6781db12a66f038"
}

After inputting this for example:

"Go hiking"

Why am i not getting the input as my result?