> For the complete documentation index, see [llms.txt](https://docs.lipachat.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.lipachat.com/api/templates/intro.md).

# Intro

Overview

WhatsApp requires *message templates* for any business-initiated communication that occurs outside of an active session. A *session* automatically begins whenever a user sends a message to your WhatsApp number and remains open for 24 hours. During an active session, you can exchange free-form messages without additional constraints.

***

When to Use a Message Template

1. **Outside the 24-hour Session Window**

If more than 24 hours have passed since the user last messaged you, any new outbound message you send must use a *WhatsApp message template*.

2. **One-time PIN (OTP), Marketing broadcasts, or Transactional Updates**

Templates are perfect for crucial communications such as OTPs, receipts, or other messages that must be sent when no active session exists.

***

#### Getting a Template Approved

{% stepper %}
{% step %}
**Create the Template**

Define the content of your message, including any placeholders (e.g., `{{1}}`, `{{2}}`) for personalization.
{% endstep %}

{% step %}
**Submit for Approval**

Once you submit a template, WhatsApp usually approves or rejects it within a few minutes using an **automated review**. If the system can’t handle it automatically, the template is sent for manual review, which may take up to 48 hours..
{% endstep %}

{% step %}
**Use the Approved Template**

After approval, you can send the template to any user. If the user replies, a new 24-hour session begins, allowing you to switch to free-form messages again.
{% endstep %}
{% endstepper %}

***

#### Key Points to Remember

* **24-Hour Session Window**: A session starts when a user sends a message to your business and remains active for 24 hours.
* **Unlimited Messages During a Session**: You can send and receive any number of messages while the session is open.
* **Renewing the Session**: If the user replies to your template or any message, it reopens or extends the session window by another 24 hours.
* **Template Content**: Templates must comply with WhatsApp’s policies. Ensure that your templates are clear and concise, and follow WhatsApp’s acceptable use guidelines to avoid rejection.

Read more [here](/reference/template-review-and-approval.md)