Open Instagram and go to your profile by tapping your profile picture. Tap the three horizontal lines (menu icon) in the top-right corner. Select "Discover People" or "Settings" > "Account" > "Contacts syncing.". Enable "Connect Contacts" to sync your phone contacts with Instagram. Instagram will suggest profiles based on your synced contacts.
Use the search bar at the bottom of the Instagram home screen. Enter a specific username, name, or keyword related to the contact you're looking for.
Go to your profile and tap the menu icon. Select "Discover People", where Instagram will suggest people based on mutual friends, interests, or your contact list.
Visit a friend's profile, then look at their followers or following list. You might find the contact you're looking for.
If you’ve had prior conversations with someone, tap the paper airplane icon in the top right corner of the home screen to search within your messages