you can append ng model value to the default specific domain available in span input group
<label for="inputEmail4">Email</label>
<div class="input-group">
<input type="text" class="form-control" autocomplete="off"
id="email" [(ngModel)]="email" name="email">
<div class="input-group-append">
<span class="input-group-text pt-1">{{defaultEmail}}</span>
</div>
</div>