How to link a site to a Telegram bot to get a one-time password?

Question

Bots

a site where people buy access to the Telegram quest bot. By access, I mean that the bot has a clear story algorithm and asks for a password to start the game. This password is generated on the site immediately after payment (which is also an interesting question, how to connect these processes) and is displayed to the buyer on the quest page. Enter the password in the bot - the game starts. In the bot code, passwords are stored as a list.

My question is: how to make the site send a fresh password to the Telegram bot so that the bot adds it to its list and after entering it calmly starts the game? There is an idea to make a similar scheme with a bot that reads information from the site, for example, exchange rates, quotes, etc., so that the quest bot reads that password and adds it to the list of passwords, and deletes it at the end of the game. There is also an idea to send a password to the user's Telegram, but as far as I know, bots cannot send messages until the user starts working with it.

For clarity, I am attaching a screenshot of the payment page, where the password is also displayed. The layout of the site began just yesterday, but I just decided to find out the difficult points in advance, so there is no site code yet.


(The "Password" line before payment has such a "spiral" that will open after and show the generated password)