> For the complete documentation index, see [llms.txt](https://dev.guardian.hedera.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dev.guardian.hedera.com/guardian/standard-registry/schemas/system-policy-schemas.md).

# Types of Schemas

There are four types of Schemas:

1. [System Schemas](#system-schemas)
2. [Policy Schemas](#policy-schemas)
3. [Tag Schemas](#tag-schemas)
4. [Module Schemas](#module-schemas)

To display System / Policy Schemas in the GUI, we have added a toggle in the Schemas tab.

<figure><img src="/files/ks50byn0wmmZfGLJ2RV4" alt=""><figcaption></figcaption></figure>

## System Schemas

Whenever an account is created, System Schemas are generated automatically.

<figure><img src="/files/2fO3NClKCw3ze9nbUeFt" alt=""><figcaption></figcaption></figure>

{% hint style="info" %}
Note: By default System Schemas cannot be edited/deleted.
{% endhint %}

## Policy Schemas <a href="#policy-schemas" id="policy-schemas"></a>

This is the second option in the Schemas tab. This option displays all the Policy Schemas related to all the created/imported Policies in the Policies tab.

The below screenshot shows the Policy Schemas of an imported Policy (i.e. iRec).

<figure><img src="/files/8nrSt8tUp0qSWlFrUI6r" alt=""><figcaption></figcaption></figure>

We also have a filter, where by default, all the Schemas of Policies are shown. We can also select a particular Policy to show the Schemas of the selected Policy.

<figure><img src="/files/IF2Z8XMEOY3Vs2Y0osDO" alt=""><figcaption></figcaption></figure>

## Tag Schemas

Tags can have attached/linked documents. To add a document to the tag a schema is required. Such documents can be found under the [**Tag Schemas**](/guardian/standard-registry/schemas/tag-schema.md) section.

## Module Schemas

Module schemas needs to define minimum set of fields in module variable with type “schema”.

### Creation of Schemas

To create module schema, we need to click on Create New button:

<figure><img src="/files/KC2yRI5FJgrvVe6ru35t" alt=""><figcaption></figcaption></figure>

<figure><img src="/files/HaLxe6Elc9oqw8g5iQ1B" alt=""><figcaption></figcaption></figure>

### Using schemas:

Select module schema in “BaseSchema” field in module variables section

<figure><img src="/files/fwzlm8KxcBXuTdG1r1MP" alt=""><figcaption></figcaption></figure>