<h4 class="mt-4">

  On outer div

</h4>

<div class="form-outline timepicker" data-mdb-timepicker-invalidLabel="Testing">

  <input type="text" class="form-control" id="form1"  />

  <label class="form-label" for="form1" >Select a time</label>

</div>

​

<h4 class="mt-4">

  On input

</h4>

<div class="form-outline timepicker" >

  <input type="text" class="form-control" id="form2" data-mdb-timepicker-invalidLabel="Testing" />

  <label class="form-label" for="form2" >Select a time</label>

</div>

​

<h4 class="mt-4">

On Label

</h4>

<div class="form-outline timepicker" >

  <input type="text" class="form-control" id="form3"  />

  <label class="form-label" for="form3" data-mdb-timepicker-invalidLabel="Testing">Select a time</label>

</div>