Open Telegram
Open the chat you want to back up
Tap the chat name or profile icon
Check whether it is a cloud chat or a secret chat
For cloud chats, use Telegram Desktop
Open Telegram Desktop and sign in
Go to Settings
Open Advanced
Select Export Telegram Data
Choose the chat or chats you want to back up
Select the data types you want to export
Choose the export format
Start the export
Save the exported files to your device
For secret chats, take screenshots or copy important messages manually
Save media files separately if needed
Regularly repeat the export to keep backups updated