You have three options to remove your Telegram account on multiple devices. These options depend on which device you wish to log out of your Telegram account.
iPhone & Android
Both Android and iPhone have the exact same steps for logging out or removing a Telegram account. This is how you do it:
First, visit the Telegram App.
Choose Settings.
Next, click on Devices.
To find out from which device your Telegram account can be deleted, click on the Active Session section and tap it.
Click on the Terminate Sessions button.
You can click Terminate All Other Sessions to sign out of Telegram on the devices that you do not know.
PC
Click on the Hamburger Icon at the top of the Telegram App.
Next, click Settings.
Select Devices.
You can find the Active Session section and choose the device that you wish to log out of Telegram.
Next, click on the Terminate Sessions button.
To Log out of Telegram from other devices, click on Terminate all Sessions
Most Frequently Asked Questions
Can someone else use my Telegram Account?
There are several ways someone can access your Telegram account. They could hack your phone to access Telegram apps or log into your Telegram account to make use of it.
What is the best way to see which devices are logged into Telegram?
Click the three lines menu at the top of Telegram feed to see the list of logged in devices. Next, enter the Settingsmenu and select devices to view a complete list of connected devices in the Activity section. This section shows the brand and model of each device.
Source: https://writtenbygeeks.com/how-to-remove-telegram-account-from-other-devices/