<div class="col-md-2">
    <label>Length of Stay</label>
        <div class="form-group d-inline-block">
              <input type="text" class="form-control">
              <select class="custom-select">
                   <option disabled selected>Select Length</option>
                   <option value="Years">Years</option>
                   <option value="Months">Months</option>
                   <option value="Days">Days</option>
               </select>
         </div>
</div>