<div class="filter mb-3">
<form class="form-inline">
<div class="form-group" style="flex-grow: 1;">
<input type="text" class="form-control w-100" id="inputPassword2" placeholder="ex : tag:capacitation">
</div>
<button type="submit" class="btn btn-primary ml-2">filtrer</button>
</form>
</div>