How can i add required field while creating a form?

Answer 1

Add 'required' => true to the array:

{!! Form::input('number', 'mobile',  null, ['required' => true, 'type' => 'number'....

Answer 2

You need to check it with your next_button using jquery

  <div class="form-group">
    <div class="col-md-4">
      <label class="control-label">Mobile Number:</label>
    </div>
    <div class="col-md-8">
      {!! Form::input('number', 'mobile',  null, ['type' => 'number', 'min' => 0, 'id' => 'mobile', 'class' => 'input-lg form-control TabOnEnter', 'placeholder' => 'Eg: 9876543210', 'tabindex' => 15]) !!}

    <button style="margin-right:20px;" class="next_button btn btn-info active nextBtn btn-md pull-right" type="next" >Next</button>
    </div>
  </div>

$(document).ready(function(){
   $('.next_button').click(function(event){
        if ($('#mobile').val() == ""){
            event.preventDefault();
            alert('Enter the number');
        }
    });
});

Added next_button class in your existing code