# 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)


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.lipachat.com/api/templates/intro.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.