> ## Documentation Index
> Fetch the complete documentation index at: https://docs.automate.ax/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> Automate.ax automations are TypeScript programs.
> Use Bun for installation and command examples.
> Use Automate.ax for the product name and automate.ax for the package, CLI, and domain.
> Treat documented public APIs as current; do not invent transitional or deprecated names.

# Create custom field

> Create a custom field in Apollo.

`apollo.createCustomField` creates a custom field for contacts, accounts, or deals.

```ts automations/create-apollo-custom-field.automation.ts theme={null}
import { automation, onDashboardRun } from "automate.ax"
import { apollo } from "automate.ax/apollo"

export default automation("Create a renewal field", () => {
  onDashboardRun({ title: "Create a renewal field" })
  apollo.createCustomField({
    label: "Renewal owner",
    modality: "account",
    type: "string",
    maxLength: 120,
  })
})
```

`modality` accepts `contact`, `account`, or `opportunity`. `type` accepts `string`, `textarea`, `number`, `date`, `datetime`, or `boolean`. Returns the new field's update-ready composite ID, label, modality, type, and optional maximum length.