You can sync events between your outlook calendar and Zoho Crm to do this

1.  Go to setup in Zoho CRM

2.  If your email integration is not setup, set that up first, 

3.  Go to marketplace

4.  Go to Microsoft

5.  Go to Events, turn on, and enter your credentials

If you don't have O365 or exchange server settings you can click on outlook tab, select your version of outlook, and download and install the outlook plugin

You can also view a video here on how to set this up

https://www.youtube.com/watch?v=qJ4m81-B09s