For web platform:

You have an option to stay logged in by checking the corresponding check box on the main login page. Kindly note, that you will remain logged only on this device only, until you log out.

For app:

The application will not ask you to enter your box code and verification code from SMS every time you open it. However, you will be asked to enter the 6-digit passcode you have set up to unlock the app. If you have the Face/Touch ID enabled, it will let you unlock the app without entering the 6-digit passcode.