# Add-ons

> Smart Fields for particular websites, like LinkedIn or HubSpot, added from the marketplace.

Add-ons are Smart Fields for particular websites. They read details from the page you’re on, like the name of the person you’re messaging on LinkedIn or the pull request you’re reviewing on GitHub, and fill them into your snippets.

```
Hi {{li.firstname}}, thanks for connecting!
```

## Where they come from

You add them from the [marketplace](https://simplefill.app/marketplace?type=smart-field). Each add-on brings a set of fields for its websites. See [Smart Field add-ons](https://simplefill.app/docs/add-ons) for the list, how to add one, and how to update or remove it.

## Where you find their fields

- In the dashboard, under **Fields** > **Add-ons**, with the websites each add-on works on.
- In the rich text editor, under **Insert field**, in a section named after the add-on, like **HubSpot** or **LinkedIn**.
- On a page, by typing the trigger and a field’s shortcut, like `;li.firstname`.

## How they fill in

An add-on’s fields fill in only on its own websites. Elsewhere, they’re left empty and SimpleFill says why. Like any [Smart Field](https://simplefill.app/docs/smart-fields), they take [Transforms](https://simplefill.app/docs/transforms): `{{li.name | uppercase}}`.

Source: https://simplefill.app/docs/add-on-fields