You can bring your chat history with all media and files to Telegram from other apps like WhatsApp, Line and KakaoTalk. Using the native export tool in those apps, share the exported file with Telegram, and then choose the Telegram chat where you want those messages to be added.
To move a chat from WhatsApp on iOS, open the Contact Info or Group Info page in WhatsApp, tap Export Chat, then choose Telegram in the Share menu.
From WhatsApp on Android, tap ⋮ > More > Export Chat, then choose Telegram in the Share menu.
