> For the complete documentation index, see [llms.txt](https://help.modelreef.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.modelreef.io/help/permissions-and-collaboration/attachments.md).

# Attachments

This article explains how **attachments** work in Model Reef.

You will learn:

* What kinds of files you can attach.
* Where attachments can be added.
* How attachments support documentation, review and audit.

Attachments keep evidence and context close to the assumptions they support.

{% stepper %}
{% step %}

### What you can attach

You can upload files such as:

* PDFs (for example contracts, board packs, loan agreements).
* Spreadsheets and CSV files.
* Images (for example screenshots or charts).
* Other relevant documents that help explain or justify assumptions.

Attachments are stored with the model and associated with specific objects.
{% endstep %}

{% step %}

### Where attachments can be added

Attachments can be linked to:

* Variables and drivers, to document the source of numbers.
* Branches, to document entity or project level materials.
* Data Library entries, to show source data or methodologies.

This makes it easy to find the documentation relevant to a particular assumption or part of the model.
{% endstep %}

{% step %}

### Roles and access to attachments

Permissions behave as follows:

* **Owners and Editors**
  * Can upload, update and remove attachments on objects they can access.
* **Viewers**
  * Can view and download attachments on objects they can access.
  * Cannot upload or delete attachments.

Branch level permissions still control which attachments are visible to each user based on where the attachment is linked.
{% endstep %}

{% step %}

### Best practices for attachments

To use attachments effectively:

* Attach key source documents to the variables they support.
* Include a note summarising what the attachment contains and which numbers it supports.
* Keep naming consistent so that it is clear which version of a document is current.
* Remove obsolete attachments if they are replaced, or clearly label them as superseded.

This improves auditability and reduces time spent searching for source documents.
{% endstep %}
{% endstepper %}

***

## Related articles

* [Board/Investor Reporting for Clients](/use-cases/accounting-firms-and-advisors/board-investor-reporting-for-clients.md)
* [Investment & Transactions](/how-tos/investment-and-transactions.md)
* [Subcategories](/help/building-your-model/subcategories.md)
* [How to Enter Values](/syntax/how-input-fields-work/how-to-enter-values.md)