> ## Documentation Index
> Fetch the complete documentation index at: https://onextel-09023014.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# About WhatsApp

> What the WhatsApp Business Platform gives you, the rules that shape every message, and what to set up first.

WhatsApp reaches customers in the app they already use all day, in a thread they can reply to.
Businesses send through Meta's
[WhatsApp Business Platform](https://developers.facebook.com/documentation/business-messaging/whatsapp/get-started),
and OneXtel connects you to it — so the platform's rules are Meta's, and they shape how you plan
every campaign.

## The one rule that shapes everything

Meta separates messages into two kinds, and which one you can send depends entirely on when the
customer last wrote to you.

| | Template message | Session message |
| - | - | - |
| When you can send it | Any time | Only within **24 hours** of the customer's last message |
| Approval | Pre-approved by Meta before first use | None — write it freely |
| Typical use | You start the conversation: an order update, a reminder, an offer | You reply while a conversation is live |

That 24-hour window is Meta's customer service window. Once it closes, a free-form reply will not
send, and you have to fall back to an approved template. Support teams feel this first.

## Message categories

Every template is approved into a category, which decides what it may say and how it is priced.

| Category | For |
| - | - |
| [Marketing](/guides/whatsapp/template-categories-marketing) | Offers, launches, re-engagement |
| [Utility](/guides/whatsapp/template-categories-utility) | Updates about something the customer already did — orders, payments, bookings |
| [Authentication](/guides/whatsapp/template-categories-authentication) | One-time passcodes |

<Warning>
  **Getting the category wrong is the most common reason a template is rejected.** A message that
  reads like an offer will not pass as utility, however it is labelled. See
  [Template categories](/guides/whatsapp/template-categories).
</Warning>

## What you can send

Text, images, video, documents and location, with quick-reply buttons and call-to-action buttons
that open a link or dial a number. Customers can reply, and their replies come back to you —
which is the part that makes WhatsApp a conversation rather than a broadcast.

## Before your first message

<Steps>
  <Step title="A WhatsApp Business Account and a number">
    A number that is not already in use on the consumer WhatsApp app, with a display name Meta
    approves. See [Onboarding WhatsApp](/guides/whatsapp/activation).
  </Step>

  <Step title="Approved templates">
    Anything that starts a conversation needs an approved template, so write these before you
    plan the campaign, not after. See
    [Create templates](/api-reference/whatsapp/templates-create).
  </Step>

  <Step title="Opt-in, and a way to opt out">
    Meta requires customers to have agreed to hear from you, and to be able to stop. See
    [Opt in and opt out](/api-reference/whatsapp/opt-in-opt-out).
  </Step>
</Steps>

<Note>
  Meta also applies quality ratings and messaging limits per number, based on how customers react
  to your messages. Blocks and reports lower your limit; useful, expected messages protect it.
</Note>

## Where to go next

<CardGroup cols={2}>
  <Card title="Send your first campaign" icon="paper-plane" href="/guides/whatsapp/quickstart">
    Build and launch WhatsApp campaigns from the portal.
  </Card>

  <Card title="Get the channel switched on" icon="circle-check" href="/guides/whatsapp/activation">
    What you supply, what you decide, what to have ready.
  </Card>

  <Card title="Send from your own code" icon="code" href="/api-reference/whatsapp/overview">
    The WhatsApp API — templates, sends, callbacks and error codes.
  </Card>

  <Card title="Send from your marketing platform" icon="plug" href="/plugins/overview">
    MoEngage, WebEngage and the other connectors.
  </Card>
</CardGroup>

## Reference

* [WhatsApp Business Platform](https://developers.facebook.com/documentation/business-messaging/whatsapp/get-started) — Meta's own documentation for the platform underneath
* [WhatsApp error codes](/api-reference/whatsapp/error-codes) — what each Meta rejection means


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