Google has enabled Guest User Mode and Multi User Mode in Android Lollipop. This feature is a boon to users who are holding multiple Google Accounts. It is also helpful to users who want to loan the handset to someone without worrying about the privacy of their data.
What is Multi User
Any Google user has a Google Account tied to the range of Google Products like Gmail, YouTube, Google Drive, etc. In Android versions prior to Lollipop, the owner of the Android Handset used to be asked to fill in the credentials and that handset is locked to the particular user.
Now take the example of anyone who is having two Gmail accounts. He/She can still add accounts in the handset and send receive mail from multiple accounts. But with Lollipop, it means that another user can have his/her own space on the same handset.
How to enable Multi User and Guest Mode
Go to Settings, Device and Users. Guest Mode can be enabled from here. Also a new user can be added here. Just enter the credentials of the user and you are good to go. The handset reboots into the new user mode. The user gets its own wallpaper and settings. The users also gets a separate storage. The owner can give permissions to the user to use the owner apps.
What is Guest Mode
Guest Mode is always present in the Android handset. It can be enabled to safely loan your phone to use to anyone. After the Guest Mode is enabled make sure that permissions for each app and feature is set prior to handing over the phone to someone. Guest Mode is like a private mode. Use the Users screen to revert back to the owner mode.