---
title: "Collecting Email and Mobile Phone Number: What You Need To Know"
description: "In OnceHub, the Email and Phone fields are more than just contact methods, they are unique identifiers."
url: "https://help.oncehub.com/product/booking-calendars/booking-forms/collecting-email-and-mobile-phone-number-what-you-need-to-know"
---

In OnceHub, the **Email** and **Phone** fields are more than just contact methods, they are **unique identifiers**. These fields allow OnceHub to recognize a contact and determine if they are a new visitor or an existing contact in your **Contact Database**.

OnceHub provides **full flexibility** to choose which identifiers you collect across both web-based (GUI) and Phone Booking channels. Your choice of identifier typically depends on your booking channel:

* **Web-based Scheduling (GUI):** By default, Email is set as a mandatory field to ensure guests receive calendar invites and automated notifications.
* **Phone Booking:** The Phone field should be used as the contact identifier as this reduces friction during conversational scheduling while allowing for SMS confirmations.

***

## 1. Collecting Email as Your Identifier

[Section titled “1. Collecting Email as Your Identifier”](#1-collecting-email-as-your-identifier)

Collecting an email address as the primary identifier is the **recommended setup for all web-based scheduling**. This ensures that all calendar invites and automated notifications are delivered.

## How to set Email as the Identifier:

[Section titled “How to set Email as the Identifier:”](#how-to-set-email-as-the-identifier)

1. Navigate to your **Booking Form** editor.
2. Select the **Contact Email** field to open its settings on the right-hand panel.
3. Toggle **Answer required** to ON.
4. Click **Save** to confirm the changes.

**If you are using Phone Booking**

For the best Phone Booking experience, the Contact Email field’s **Do not ask for email address when bookings are made via phone booking** setting is enabled by default.

This setting allows you to maintain a single Booking Calendar for both web-based (GUI) and Phone Booking guests. It prevents forcing a caller to provide an email address during the phone conversation flow. Add a Phone field and enable SMS notifications in the Notifications tab to ensure your guest still receives all necessary reminders.

***

## 2. Collecting Only Mobile Phone Number as Your Identifier

[Section titled “2. Collecting Only Mobile Phone Number as Your Identifier”](#2-collecting-only-mobile-phone-number-as-your-identifier)

For **Phone Booking** and **phone-first businesses** where **speed is critical** or guests prefer **SMS** notifications, setting the **Phone** field as the identifier is ideal.

## How to set Phone as the Identifier:

[Section titled “How to set Phone as the Identifier:”](#how-to-set-phone-as-the-identifier)

1. Navigate to the **Booking Form** editor.
2. Select the **Phone** field to open its settings on the right-hand panel.
3. Toggle **Answer required** to ON. **IMPORTANT:** We highly recommend selecting the **Contact details and SMS (requires consent)** checkbox to ensure compliance and SMS notification delivery.
4. Click **Save** to confirm the changes.

To learn more, read our [**Scheduling Without Email: What You Need To Know**](https://help.oncehub.com/contact-management/scheduling-without-an-email-what-you-need-to-know) article.

***

## Frequently Asked Questions (FAQs)

[Section titled “Frequently Asked Questions (FAQs)”](#frequently-asked-questions-faqs)

**What happens if Email and Mobile Phone are both collected?**

**A:** If both fields are provided, **Email remains the primary identifier**. OnceHub will prioritize matching the contact based on their email address. The phone number will be updated or added to that specific contact record.

**What if I do not collect Email OR Mobile Phone?**

**A:** If neither field is collected:

* OnceHub cannot recognize the guest. A **new contact** will be created for every activity.
* OnceHub will have no way to send calendar invites or notifications.

To learn more, read our [**How Contacts Are Identified In OnceHub**](https://help.oncehub.com/contact-management/how-contacts-are-identified-in-oncehub/) article.