Android 4.2.2 introduces a new multiple users feature, which allows many people to share the same device, but have separate user accounts. Each user account can have its own wallpaper, browser history, apps, email accounts, google accounts etc. much like the user accounts on, for example, a PC. Each user can login from the lockscreen, and each account can be locked with any of the normal methods, such as a password or a pattern.
Most tablets with Android 4.2.2 already have multiple users enabled. However, some tablets such as my Pendo PNDPP410GPBLK have this feature disabled, and it also seems to be disabled on phones.
To enable multiple users, your device must be rooted. You also need a terminal app such as Android Terminal Emulator. The following instructions should work on both phones and tablets. Be aware that, while these instructions worked for me, there may be a small chance that something could go wrong, so having a backup of your device's ROM would be useful, just in case. Here are the steps:
1. Open up your terminal app, and type the command "su" (without quotes, and you need to press enter after typing each command).
2. Type "pm get-max-users". This command will show the maximum number of users the device currently allows. If this command returns an error instead of a number, your ROM probably does not have any multiple user functionality, and the following instructions may not work.
3. Type "mount -o rw,remount /system". This allows you to write to the system files until the next reboot, which is necessary for the following command.
4. Type "echo fw.max_users=4 >> /system/build.prop". This sets the maximum number of users the device allows, and you can change the number 4 to whatever number you want.
5. Reboot your device.
6. The Users section should now be in the Settings app, under "DEVICE". You should be able to add a new user by tapping on "ADD USER".