[Vuejs]-How to bind a value in json object in vue js

you can use computed https://v2.vuejs.org/v2/guide/computed.html#Computed-Setter
Something like this:

computed: {
  title: {
    set: function(value){
      this.todo.title = value
    },
    get: function() {
      return this.todo.title
    }
  }
}

Then bind computed property with input

<v-text-field
  v-model="title"
  outlined
  full-width
  label="Another input"
></v-text-field>