Q: What are usernames? How do I get one?
You can set up a public username on Telegram. It then becomes possible for other users to find you by that username — you will appear in contacts search under ‘global results’. Please note that people who find you will be able to send you messages, even if they don't know your number. If you are not comfortable with this, we advise against setting up a username in Telegram.
You can set up a username in Settings and use the universal search box in the chats list to search for chats, messages, and usernames.