error text in bootstrap 4 fields code example

Example 1: bootstrap forms

<form>
  <div class="form-group">
    <label for="exampleInputEmail1">Email address</label>
    <input type="email" class="form-control" id="exampleInputEmail1" aria-describedby="emailHelp" placeholder="Enter email">
    <small id="emailHelp" class="form-text text-muted">We'll never share your email with anyone else.</small>
  </div>
  <div class="form-group">
    <label for="exampleInputPassword1">Password</label>
    <input type="password" class="form-control" id="exampleInputPassword1" placeholder="Password">
  </div>
  <div class="form-check">
    <input type="checkbox" class="form-check-input" id="exampleCheck1">
    <label class="form-check-label" for="exampleCheck1">Check me out</label>
  </div>
  <button type="submit" class="btn btn-primary">Submit</button>
</form>

Example 2: bootstrap email address validation

<form> <!--make sure you add this inside a form-->
  <div class="form-group"> <!--required to start the form container-->
    <label for="InputEmail">Email address</label> <!--"for" needs to match the "id" on the next line to bind it-->
    <input type="email" class="form-control" id="InputEmail" placeholder="Enter email"> <!--id, class, and type are required for it too look right, placeholder will edit the text inside the input box-->
    <small class="form-text">We'll never share your info.</small> <!--applies small underlining text-->
  </div>
  <div class="form-group">
    <label for="Password">Password</label>
    <input type="password" class="form-control" id="Password" placeholder="Password">
  </div>
  <div class="form-check">
    <input type="checkbox" class="form-check-input" id="Check">
    <label class="form-check-label" for="Check">Check out</label>
  </div>
  <button type="submit" class="btn btn-primary">Submit</button>
</form>