Telegram offers users additional security and privacy features, including the ability to hide their phone number in private chats or groups. This can be done through the Telegram App’s Settings menu. Select 'Privacy and Security,' followed by 'Phone Number,' and then select 'Nobody' to prevent anyone from seeing the phone number. While this will stop people in the chat from seeing a user's phone number, those who already have the number saved on their phone will still be able to see it.