Article: The Telegram icon looks like a white paper plane inside a blue circle. You can find it on your phone or tablet's Apps menu. This button is in the upper-right corner of your chats list. It will switch from your chats list to the search page, and reveal the Search bar at the top of your screen. If Telegram opens up to a chat conversation, tap the back button to go back to your chats list and reveal the magnifying glass. Search a contact by typing their name in the Search bar. Matching search results will appear on your screen as you type. It will open your chat conversation with this contact in full-screen. Alternatively, you can tap a chat conversation on your chats list. Your contact's profile picture and name will appear at the top of the chat conversation. Tap their name or picture to open their account summary on a new page. This field shows your contact's username below their phone number at the top of their account summary.

What is a summary?
Open the Telegram app on your Android. Tap the white magnifying glass icon. Enter a contact's name. Tap the contact you want to look up on the list. Tap your contact's name or profile picture. Find the Username field under the Info heading.