Here are step-by-step guides showing you how to deactivate your Telegram account and how to delete your Telegram account. https://howtodelete.org/delete-telegram-account/

1. Delete Telegram
Account
WWW.HOWTODELETE.ORG

2. Things to consider before you
deactivate Telegram account
 You can’t delete Telegram Account using mobile or desktop
app. You got to use a web browser like Google, Firefox, Edge,
etc. either from your phone or PC.
 All your messages, groups, and bots will be removed
completely, and the channels you have created will be taken
over by the admin.
 Entire contacts on Telegram will be lost permanently.
 The permanent deletion of Telegram account cannot be
reinstated.
 Though you can create a new account using the same
number after some time, you can’t restore your chat history
and contact list.

3. How to Delete Telegram Account
Permanently?
 Visit Telegram account
Deletion page from your favorite
web browser either through mobile
or from your laptop/PC.
 Enter the phone number with which
you have created the Telegram
account that you want to delete and
then click on Next. The number
should be in an international format
i.e., it should be preceded by the
country code and area code.

4.  You’ll receive confirmation code in
Telegram application (not in SMS)
immediately. Go back to the web
browser and then type the code
manually in the field provided for the
same after that click on “Sign in”. The
code is case sensitive so entering it,
make sure that even the case of the
letter matches.

5.  In the next page, read and
understand what will happen once
you delete Telegram account. Scroll
down to the bottom of the page and
type the reason for leaving Telegram.

6.  A confirmation sub window will pop up. If you
haven’t made last minute change to your thought,
then confirm your choice to delete Telegram account
by clicking Yes, Delete my Account.

7. Steps to enable Account Self-destruct
Option
 Open Telegram application
either on your phone or PC.
 Tap on the menu icon (≡)
that lies towards the top left
corner of the page and click
on “Settings” option from the
menu pane that slides out.

8.  Swipe down and tap on “Privacy and
Security”.

9.  In the Privacy and Security
page under the Advanced
option tap on “Delete my
Account if away for”.

10.  Choose the period to self-destruct.
Don’t use the Telegram for the period that
you’ve chosen above and your account
including all the data in it will be deleted
permanently.
But it won’t stop others to contact you in
Telegram. So, we recommend you to uninstall
the application from your phone as well as PC.

11. Uninstall Telegram from Android
phone
 Go to the list of the application.
 Tap and hold the Telegram icon.
 After holding it for a while drag it towards the top of
the screen where you will see two option “Cancel”
and “Uninstall”.
 Drag the application to the Uninstall tab and leave
it.
 Confirm your choice and the application will be
deleted from your Android phone.

12. To uninstall the application from PC
 Click the “Windows” icon at the bottom left corner
of the screen of your desktop.
 You will see the list of all the programs on your
desktop arranged in alphabetical order. Scroll down
and find the Telegram.
 Right-click in the Telegram application and then click
on the “Uninstall” option.

13.  It will redirect you to control panel where you can
uninstall or change a program. Scroll down and find
Telegram and double click on it.
 A pop-up window will appear, asking you ‘ Are you
sure want to completely remove Telegram Desktop
and all of its components?’. Click ‘Yes,’ and the app
will be uninstalled from your PC.

14. Source:
https://howtodelete.org/delete-telegram-