itflow/project_add_modal.php

<div class="modal" id="addProjectModal" tabindex="-1">
  <div class="modal-dialog">
    <div class="modal-content bg-dark">
      <div class="modal-header">
        <h5 class="modal-title"><i class="fas fa-fw fa-project-diagram mr-2"></i>New Project</h5>
        <button type="button" class="close text-white" data-dismiss="modal">
          <span>&times;</span>
        </button>
      </div>
      <form action="post.php" method="post" autocomplete="off">

        <input type="hidden" name="client_id" value="<?php if (isset($_GET['client_id'])) { echo $client_id; } else { echo 0; } ?>">

        <div class="modal-body bg-white">

          <div class="form-group">
            <label>Project Name <strong class="text-danger">*</strong></label>
            <div class="input-group">
              <div class="input-group-prepend">
                <span class="input-group-text"><i class="fa fa-fw fa-project-diagram"></i></span>
              </div>
              <input type="text" class="form-control" name="name" placeholder="Project Name" required autofocus>
            </div>
          </div>

          <div class="form-group">
            <label>Description</label>
            <div class="input-group">
              <div class="input-group-prepend">
                <span class="input-group-text"><i class="fa fa-fw fa-angle-right"></i></span>
              </div>
              <input type="text" class="form-control" name="description" placeholder="Description">
            </div>
          </div>

        </div>
        <div class="modal-footer bg-white">
          <button type="submit" name="add_project" class="btn btn-primary text-bold"><i class="fas fa-check mr-2"></i>Create</button>
          <button type="button" class="btn btn-light" data-dismiss="modal"><i class="fa fa-times mr-2"></i>Cancel</button>
        </div>
      </form>
    </div>
  </div>
</div>