Hi is there any documentation for anonymous telegram numbers? would like to find if it has any on-chain functions

https://github.com/TelegramMessenger/telemint

You can look whether there are such functions in the code. Just see the contract in explorer.

Thanks

I can't see any function for telegram numbers to get the verification code on chain. It's only possible manually through fragment?

Yes, verification codes are created by Telegram+Fragment and don't use blockchain neither for generation nor for storing.

Thanks mate. I had a thought to use numbers in a contract to borrow numbers to other users but as long I have to get the verification code manually, it wouldn't work

Yes. Though, it's possible to base other services on such numbers — just without using Telegram verification codes.