Go to https://my.telegram.org/auth
Enter your Telegram phone number in international format
Open Telegram and copy the login code sent by Telegram
Paste the code on the Telegram authorization page
Select “Delete Account”
Enter a reason if required
Click “Delete My Account”
Confirm by selecting “Yes, delete my account”
Open Telegram on your device
Go to “Settings”
Select “Privacy and Security”
Tap “If Away For”
Choose the inactivity period for automatic account deletion