Collapse div doesn't work in an embadded form

Hi! I would like to hide some divs when needed. For this purpose, I decided to use class=“collapse”
so it looks like:
but when I put on HIDDEN DIV I get this:
my HTML form is:

<form role="form">
    <html lang="ru">
        <meta charset="utf-8">
        <script src="angular.min.js" type="text/javascript"></script>
        <script src="bootstrap.min.js" type="text/javascript"></script>
        <script src="camunda-bpm-sdk-angular.js" type="text/javascript"></script>
        <link href="" rel="stylesheet"/>
    <script cam-script type="text/form-script">
   inject(['$rootScope', function($rootScope) {
      $scope.userName = $;
  var mkdPpoInfo = $scope.mkdPpoInfo = {
        entrances : []
    <!-- script -->
  camForm.on('form-loaded', function() {
      name: 'application',
      type: 'Object',
      value: mkdPpoInfo,
      valueInfo: {
        serializationDataFormat: 'application/json',
        objectTypeName: 'ru.sec2.model.MKDPpoInfo'
    <body class="bg-light">
    <div class="mb-3">
        <label for="orderObjectId">Serial number </label>
        <input type="text" class="form-control" id="orderObjectId" ng-model="mkdPpoInfo.orderObjectId" >
    <div class="tab-content faq-cat-content">
        <div class="tab-pane active in fade" id="faq-cat-1">
            <div class="panel panel-default panel-faq">
                <div class="panel-heading">
                    <a data-toggle="collapse" data-parent="#accordion-cat-1" href="#faq-cat-1-sub-1">
                        <h4 class="panel-title">
                            HIDDEN DIV
                            <span class="pull-right"><i class="glyphicon glyphicon-plus"></i></span>
                <div id="faq-cat-1-sub-1" class="panel-collapse collapse">
                    <div class="panel-body">
                        First Item Category #1
                    <div class="panel-body">
                        Second Item Category #1

I use camunda.version 7.14.0
As far as I uderstand, I have a problem with bootsrap.js plugin. Could you advice me please how to added the plugin bootsrap.js.
Thanks in advance

To additional js code you need to add a plugin such as: