Zimlets are add-on applications that enhance the functionality of your client. When a Zimlet is added to ZWC, you can look at information and interact with the third-party application from within your email messages.
Several pre-configured, default Zimlets are included when ZWC is installed.
There are Zimlets that are included in the Zimbra Web Client and considered default Zimlets.
Procedure
Go to Preferences>Zimlets page.
Select the Zimlets you want to enable.
Click Save.