 
      Specify the location of the custom template
admin.py
class BookmarkletAdmin(admin.ModelAdmin):
    change_form_template = 'bookmarklet/admin/change_form.html'
It's easier to write by inheriting admin/change_form.html.
{% extends 'admin/change_form.html' %}
{% block field_sets %}
{% for fieldset in adminform %}
  {% include "admin/includes/fieldset.html" %}
{% endfor %}
Write something you like here
{% endblock %}