What can I find if I know the lock code of the other party's mobile phone?

What can be found by knowing the lock password of the other party's mobile phone is as follows:

1. Open the other party's mobile phone, access its address book, SMS, social media, email and other applications, and browse its chat history and contact information.

2. Check each other's photo albums, music, videos and other files.

3. Access some external services, such as online banking, email or cloud storage, to obtain account information that the other party may have logged in.

4. If the other party is connected to a Wi-Fi network or a Bluetooth device, it may be possible to understand the other party's network activities and common devices by looking at the connection records.