Face ID or Touch ID lock
A passcode lock over the whole app, backed by biometrics, so a borrowed phone does not expose the chat list.
iPhone and iPad
On iPhone and iPad the route is the App Store, so there is no package to inspect and no permission to unlock. Apple handles delivery, signing and updates; you tap Get and the app arrives.
App Store release · Store managed · iOS 12 and newer

Specification
iOS is also where Telegram's device-bound features live. Secret chats, the passcode lock backed by Face ID and instant camera uploads all belong to the mobile app rather than the desktop client.
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A passcode lock over the whole app, backed by biometrics, so a borrowed phone does not expose the chat list.
End-to-end encrypted conversations that live only on the two devices involved, with optional self-destruct timers.
Read a chat on the iPhone, finish the reply on a Mac. Cloud history keeps both in the same place in the conversation.
Signing in on a new iPhone brings the whole chat history back without an iCloud backup or a restore.
Install walkthrough
Open the download page and follow the iPhone entry — it opens the official App Store listing rather than a file.
Tap Get, then confirm with Face ID, Touch ID or your Apple Account password.
Open Telegram and enter your phone number; the confirmation code arrives by SMS, or inside Telegram if you are already signed in elsewhere.
Allow notifications so calls and messages reach the lock screen — without this, calls simply do not ring.
Optional: set a passcode in Privacy and Security → Passcode Lock and enable Face ID for it.
If you also use a computer, open Devices to confirm which sessions are active and end anything you do not recognise.

Nothing to migrate
Cloud chats are stored server-side, so signing in on a new device restores the whole history automatically. Only secret chats and local drafts stay behind.
If it goes wrong
| Symptom | What to do |
|---|---|
| The confirmation code never arrives by SMS | If another device is already signed in, the code is delivered inside Telegram instead. Check that app first, then request an SMS as a fallback. |
| Calls do not ring | Notification permission is missing, or Focus mode is filtering the app. Allow Telegram in Settings → Notifications and add it as an exception to your Focus. |
| iPhone storage warnings | Open Data and Storage → Storage Usage and clear cached media. Chats stay intact because the files can be fetched again from the cloud. |
| The iPad shows a different chat list | That usually means the iPad is signed in to a second account. Check the account switcher at the top of the settings screen. |
Questions
iOS 12 and newer, which covers iPhones going back several generations. Older devices are limited to the browser client.
The same app covers both, and it uses a two-pane layout on iPad so the chat list and conversation are visible at once.
No, deliberately. A secret chat exists on the two devices that created it. If you sign in elsewhere, that conversation will not appear there.
Turn off Save incoming photos in Data and Storage. Media remains viewable inside the chat, it just stops being copied into Photos.
More answers are collected on the FAQ page.
Other platforms