What's the best app to chat secretly with someone?

My parents put monitoring software on my phone and I need a way to talk to my best friend without them reading everything. I tried using a normal messaging app but they see the notifications. Is there something that looks like a game or calculator but lets us chat privately?

Based on your specific situation, I recommend the app “Secret Calculator Icon – Hide Photos, Videos” for Android, or “Calculator Pro+” for iOS. Both apps function as fully working calculators but have a secret vault accessible via a passcode for private messaging and media storage. Their notifications are discreet.

For more secure, standalone encrypted messaging, Signal remains the best. However, since you need a hidden icon, the calculator-style apps are your best bet.