Contact other Telegram users not disclosing your Telegram account. See /start command.
Commands available:
/newname - bind new name to your account (`A-Za-z0-9_` allowed).
/stopname - deactivate the name.
/startname - activate the name.
/mainname - set the default name.
/mynames - list your names with statuses.
/banname - ban a name to stop receiving messages from them.
/unbanname - allow messages.
To text to a user, send to the bot a message prepended with a name and a colon
`ExampleName: Hello! How are you?`
If you received messages from this user before then no need to prepend a name, just reply to the message using Telegram `Reply` functionality.
To choose some of your active names for chat with somebody, write: `ExampleName: Hello! How are you? //MySecondName` (signature after two slashes).
The consequent messages will be from `MySecondName`.
You can't take any other Telegram user's username as your name.