Your Account
Official telegram.org Source
As was just mentioned above, all your data will be flushed from our system: all messages, groups, and contacts associated with your account will be deleted. That said, your contacts will still be able to chat in the groups that you have created, and they will still havetheircopy of the messages you sent them. So if you want to send messages that can vanish without a trace, try using ourself-destruct timerinstead.
Termination of a Telegram account is irreversible. If you sign up again, you will appear as a new user and will not get your history, contacts or groups back. People, who have your phone number in their contacts, will be notified. The new user will be displayed as a separate conversation in their messages list and their conversation history with this new user will be empty.
Official Telegram Reference: https://telegram.org/faq
Part of the TGWAY.com Official Telegram Knowledge Base (98 Verified Q&As).