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

# Send emails to a custom field address

> Use an email address stored in a custom field as the recipient of your customer communications, so reminders reach the right person on each invoice or customer automatically.

Some invoices and customers need to reach a specific person — a billing contact that can differ from one invoice to the next. When that email address is stored in a custom field, you can use the field itself as the recipient, and Upflow pulls the right address every time it sends.

With this, you can:

* Use an email held in a custom field as the **To**, **Cc**, or **Bcc** of any email — in a workflow step, a template, a campaign, or a one-off email.
* Keep automated emails reaching the right person without copying the address in by hand
* Stay in sync with your source system — the field's current value is resolved each time the email is sent

<br />

## Before you start

The custom field must already exist and hold a valid email address. You can sync the value from your source system or enter it directly in Upflow.

Custom-field recipients use your existing **text** custom fields — there's no separate "email" field type to set up. See [Import and create custom fields into Upflow](/en-us/core-entities/others/import-and-create-custom-fields-into-upflow) for how to create a field or sync one from your ERP.

<br />

## Use a custom field as a recipient

1. Open the email you want to configure — a step in a [workflow](https://app.upflow.io/organization/-/settings/workflows), a [template](https://app.upflow.io/organization/-/settings/action-content-templates), a campaign, or a one-off email.
2. Click the **To**, **Cc**, or **Bcc** field to open the recipient picker.
3. Your custom fields appear grouped in the list — invoice fields under **Invoice fields**, alongside your customer fields and team members. Each field shows its current value so you can confirm the address.
   <img src="https://mintcdn.com/upflow-04dc27cd/MKCb-DKYIYNXzoX2/images/image-27.png?fit=max&auto=format&n=MKCb-DKYIYNXzoX2&q=85&s=252f7ae9cb277de4775fd1d5a8fd01ed" alt="Recipient picker showing the Invoice fields group with a custom field email address" width="640" data-path="images/image-27.png" />
4. Select the field. Upflow uses that field's value as the recipient, resolving the current address on each invoice or customer every time the email is sent.

<Note>
  A custom-field recipient is treated like any other typed-in email address: no contact is created, and nothing is added to the customer's contact list.
</Note>

<br />

## When a field is empty or invalid

Upflow normalizes and validates the field's value at send time.

* **Automatic actions** fall back to manual: if the field is empty or the address isn't valid, the email isn't sent automatically — it's surfaced for someone to handle manually instead.
* **Manual actions** flag the problem on the recipient — for example, *"Invoice recipient email" is missing or invalid*. Update the field's value to fix it.

If a message is sent but can't be delivered, it appears in the [Action emails not delivered](/en-us/collection-and-collaboration/emails/action-emails-not-delivered) widget as an *invalid email* — not an invalid contact, since the address doesn't belong to a contact. To resolve it, correct the value in the custom field.

<br />

## Good to know

Both customer and invoice custom fields can be used as recipients:

* **Customer fields** work everywhere — in both customer and invoice workflows.
* **Invoice fields** read the address from the invoice the email is about, so they're available wherever an invoice is in context: invoice workflows, one-off invoice emails, and the billing step of a customer workflow.

<Note>
  On a customer level workflow step — which isn't tied to a single invoice — use a customer field. If an invoice field is used in a template that runs there with no invoice in context, the email falls back to a manual action so you can choose the recipient.
</Note>

<br />

## Related articles

* [Import and create custom fields into Upflow](/en-us/core-entities/others/import-and-create-custom-fields-into-upflow)
* [Customize Collection Reminders](/en-us/collection-and-collaboration/workflows-customize-your-collection/customize-collection-reminders)
* [Templates](/en-us/collection-and-collaboration/collaboration/templates)
* [Action emails not delivered](/en-us/collection-and-collaboration/emails/action-emails-not-delivered)