app/templates/_formhelpers.html

{% macro render_field(field) %}
  <div class="form-group row">
    <label class="col-sm-2 col-form-label">{{ field.label }}</label>
    <div class="col-sm-10">
      {{ field(**kwargs)|safe }}

      <small class="form-text text-muted">
        {{ field.description }}
      </small>

      {% if field.errors %}
        <ul class=errors>
          {% for error in field.errors %}
            <li>{{ error }}</li>
          {% endfor %}
        </ul>
      {% endif %}
    </div>
  </div>
{% endmacro %}

{% macro render_field_errors(field) %}
  {% if field.errors %}
    <ul class=errors>
      {% for error in field.errors %}
        <li class="text-danger">{{ error }}</li>
      {% endfor %}
    </ul>
  {% endif %}
{% endmacro %}