Invalid token in Telegram

If you received the error message “Invalid token”, this may mean that the Api Token was used previously, or that you entered the wrong token.

If the token was previously added to the system, it cannot be added again. You need to:
1) Go to @BotFather
2) Enter the /revoke command and select the required bot, which will update the token
3) Use the new token

How do I issue a token for a bot in Telegram?