Form field description in django admin

When defining your fields in models.py:

myfield = models.CharField(max_length=100, help_text="This is the grey text")

Bookmark this link:

https://docs.djangoproject.com/en/dev/ref/models/fields/#help-text

I find myself referring to it all the time (not just for help_text, but for everything to do with model fields)!

In your forms.py file, after the

fields = ['URL',....]

add

help_texts = {"URL": "Example..."}

In addition to Timmy's answer, if you want to display some additional help text and want to have some helpful markup too, you can custom display individual form fieldsets and add a description field. Using your example, let's say that you wanted to break out the Content field into it's own fieldset block and add some verbose help text. You can do something like:

from mymodel.models import MyModel
from django.contrib import admin

"""
Custom Help Text
"""
CONTENT_HELP_TEXT = ' '.join(['<p>Here is some multi-line help',
                              'which is a long string so put',
                              'into a list which is then joined',
                              'with spaces. I can do fun things',
                              'like have <strong>bold</strong>',
                              'and some line breaks.<br/>'])
"""
Customize Admin
"""
class MyModelAdmin(admin.ModelAdmin):
    """
    Add your other customizations
    like actions, list_display, list filter, etc
    """
    fieldsets = [
        ('Content', {
            'fields':('content',),
            'description': '<div class="help">%s</div>' % CONTENT_HELP_TEXT,
        }),
    ]

admin.site.register(MyModel, MyModelAdmin)

More information in the Django docs (scroll down to the fieldsets) area.