Use a secure messaging app with end-to-end encryption
Turn off message previews on the lock screen
Enable app lock or biometric lock for your messaging app
Archive or mute conversations you want out of sight
Use a hidden or private folder if your phone supports it
Disable SMS notifications on the home screen
Delete sensitive messages after reading
Use a separate phone number for private messages
Set messages to auto-delete if the app supports it
Back up only the messages you want to keep
Keep your phone locked with a strong passcode
Hide message content in notification settings