(custom_document_model)= # Custom document model An alternate `Document` model can be used to add custom behaviour and additional fields. You need to complete the following steps in your project to do this: - Create a new document model that inherits from `wagtail.documents.models.AbstractDocument`. This is where you would add additional fields. - Point `WAGTAILDOCS_DOCUMENT_MODEL` to the new model. Here's an example: ```python # models.py from django.db import models from wagtail.documents.models import Document, AbstractDocument class CustomDocument(AbstractDocument): # Custom field example: source = models.CharField( max_length=255, blank=True, null=True ) admin_form_fields = Document.admin_form_fields + ( # Add all custom fields names to make them appear in the form: 'source', ) ``` Then in your settings module: ```python # Ensure that you replace app_label with the app you placed your custom # model in. WAGTAILDOCS_DOCUMENT_MODEL = 'app_label.CustomDocument' ``` ```{note} Migrating from the built-in document model: When changing an existing site to use a custom document model, no documents will be copied to the new model automatically. Copying old documents to the new model would need to be done manually with a {ref}`data migration `. Templates that reference the built-in document model will continue to work as before ``` ## Referring to the document model ```{eval-rst} .. module:: wagtail.documents ``` ```{eval-rst} .. autofunction:: get_document_model ``` ```{eval-rst} .. autofunction:: get_document_model_string ```