Bootstrap dropdown wont appear

Hey so my bootstrap dropdown menu wont work by clicking on it.

Heres my code:

                    <div class="dragArea row fake_input">
                        <div class="col-md col-12 form-group" data-for="name">
                            <p class="fake_input_text">{{ password }}</p>
                        </div>
                        <div class="dropdown">
                            <button class="btn btn-success display-4 dropdown-toggle" type="button" id="dropdownMenuButton" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                                Choose Length
                            </button>
                            <div class="dropdown-menu" aria-labelledby="dropdownMenuButton">
                                <a class="dropdown-item" href="#">2</a>
                                <a class="dropdown-item" href="#">4</a>
                                <a class="dropdown-item" href="#">6</a>
                            </div>
                        </div>
                        <div class="mbr-section-btn col-12 col-md-auto"><a href="{% url 'home:passwordgenerator' %}" class="btn btn-success display-4">Generate</a></div>
                    </div>

Solution

add these in head tag also do ctrl+f5 to clear the cache

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>