If that phone number is registered on Telegram, their Telegram profile will appear, and they'll be added to your Telegram contacts. If they are not on Telegram, you'll usually see an option to invite them.
Method 3: Adding a Contact by Username (Without Phone Number)
This is a great way to add people you meet in groups, online, or who prefer not to share their phone number.
Use the Search Bar:
On Mobile (Android/iOS): Tap the magnifying glass icon (search icon) at the top of the main chat list screen.
On Desktop: The search bar is typically at the top-left of the application window.
Enter the Username:
Type the person's Telegram username into the search telegram number database bar. Usernames typically start with an @ symbol (e.g., @YourFriendName). You usually don't need to type the @ when searching, but type the exact username.
Select the User:
From the search results, tap on the correct user's profile. This will usually open a direct chat with them.
Add to Contacts (Optional):
Once in the chat, tap their name/username at the very top of the chat screen to open their profile information.
You should see an option like "Add to Contacts". Tap this.
You can then enter or edit their first and last names for your contact list.