[Vuejs]-Returning empty string instead of the string 'null' vuejs

Your logic should look like this:

<v-col v-if="acctdetails.LocAdr3 === ''" cols="12">
  <v-row justify="center"></v-row> //display empty string
</v-col>

When you use v-model you usually should bind your form inputs to empty strings

const streetName = ref('')

<template>
  <input type="text" v-model="streetName" />
</template>