# Create a Tenant

Create a tenant before adding tenant-specific extensions, DIDs, routing, media, and user permissions. A tenant is the top-level container for a customer's PBX configuration.

<figure id="bkmrk-new-tenant-form-fill">![New tenant form filled with Kartoon Cars and tenant code KARTOON.](https://manual.mirtapbx.com/uploads/images/gallery/2026-06/xiatenant-create-kartoon-cars-top.png)<figcaption>New tenant form filled with Kartoon Cars and tenant code KARTOON.</figcaption></figure>## Open the tenant form

1. Log in with an administrator account that can add tenants.
2. Open **Admin** &gt; **Tenants**.
3. Select **Add** or **New** to open **Define Tenant**.

## Enter name and code

1. In **Name**, enter **Kartoon Cars**.
2. In **Code**, enter **KARTOON**.
3. Review the defaults for calling, routing, parking, billing, limits, and storage.
4. Select **Save**.

The tenant code must be unique. Use an alphabetic code such as **KARTOON**. Avoid numbers, spaces, hyphens, and underscores unless your deployment has a specific reason to use them.

## Why the code matters

MiRTA PBX uses the tenant code when creating extension usernames. The username format is:

```
<extension username>-<tenant code>
```

For example, with tenant code **KARTOON**, an extension username **201** becomes **201-KARTOON**. This keeps usernames unique across tenants even when two tenants use the same extension numbers.

After a tenant has been saved, the code field becomes read-only in the tenant form. Use the **Change** button beside the code only when you intentionally need to rename the tenant code, because extension usernames and related references depend on it.