используйте это вместо:
<i class="fas fa-info-circle text-primary " data-toggle='tooltip' title='10 digits, no
spaces, hyphens or parenthesis'></i>
как:
<div>
<form>
<div class='row'>
<div class='form-group col-md-6'>
<label for='idCellNumber'>Cell number <i class="fas fa-info-circle text-primary" data-toggle='tooltip' title='10 digits, no spaces, hyphens or parenthesis'></i><span class='asterisk'>*</span>
<span class='text-danger'>Required</span>
<span class='text-danger'>Cell number should be 10 digits</span>
</label>
<input type='text' placeholder='1234567890' class='form-control' formControlName='cellNumber' id='idCellNumber' name='cellNumber' required>
</div>
</div>
</form>
</div>
<script>
$(function() {
$('[data-toggle="tooltip"]').tooltip('toggleEnabled', {
boundary: 'window',
placement: 'top',
trigger: 'hover click'
})
})
</script>