# 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.
## System Schemas
Whenever an account is created, System Schemas are generated automatically.
{% hint style="info" %}
Note: By default System Schemas cannot be edited/deleted.
{% endhint %}
## Policy Schemas
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).
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.
## 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**](https://guardian.hedera.com/guardian/standard-registry/schemas/tag-schema) 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:
### Using schemas:
Select module schema in “BaseSchema” field in module variables section
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