Translation can be enabled in the app under Settings > Language, and then you can tap and hold a message to translate it into your language.

Telegram now offers the ability to translate any message into another language, right in the app. Messages sent with spoiler formatting will appear blurry in a chat, and you can tap the message to reveal the hidden text. When typing a message, select the text you wish to hide, tap on B/I/U in the black popover menu, and tap Spoiler. Similar to the invisible ink option in iMessage, Telegram now offers spoiler formatting for hiding text. For more reactions, tap and hold on a message bubble. You can change the emoji for this quick reaction in the app under Settings > Stickers and Emoji > Quick Reaction. With the addition of reactions, users can now double tap on a message bubble and a small thumbs-up emoji will appear at the bottom of that message. Telegram today announced it has updated its iPhone and iPad app with several new features, including message reactions, translation, hidden text, additional interactive emoji options, themed QR codes for users and channels, and more.

Telegram app on iphone