<div class="form-outline" data-mdb-input-init>

  <input type="text" id="custom-masks" class="form-control" data-mdb-input-mask-init data-mdb-input-mask="##/##/####" data-mdb-custom-mask="#" data-mdb-custom-validator="[0-9]"/>

  <label class="form-label" for="custom-masks">Custom mask</label>

</div>