I'm using Django 4.0 , using the invoice template (<a>https://preview.keenthemes.com/metronic8/demo9/dark/apps/invoices/create.html</a>).
In the add item section i have replaced the text field with a select2 tag with options filled in dynamically by django.
Ex :
<select name="item[]" class="form-select form-select-solid" data-control="select2" data-placeholder="Select an item">
<option></option>
{% for item in items %}
<option value="{{item.id}}">{{item.name}}</option>
{% endfor %}
</select>