# Updating assets

This API reference document contains information on updating assets

Since assets are a system model, and automatically added to every project, you can extend them with your own custom fields.

These fields can be updated using GraphQL mutations. 

In the following example, we have added `altText` and `caption` fields to our **Assets** model. Here, we are using an `updateAsset` mutation to change the text in them:

  **Mutation**

```graphql
mutation {
  updateAsset(
    where: {id: "<YOUR_ASSET_ID>"}
    data: {caption: "this is a new caption", altText: "this is new alternative text"}
  ) {
    id
  }
}
```

  
  **Response**

```graphql
{
  "data": {
    "updateAsset": {
      "id": "<YOUR_ASSET_ID>"
    }
  }
}
```


After successfully running this mutation, if you access your asset in edit mode, you will see the new `altText` and `caption`.

Learn more about [Mutations](https://hygraph.com/classic-docs/api-reference/content-api/mutations#update-entries).