I am looking to create "Text Area (Rich)" on Event, But there in no "Text Area (Rich)" field on Event. Can anyone please give suggestions on this?
When creating Custom Fields for Activities, You will find that Rich Text and Long Text Area Fields are not available.This is expected functionality, at this time, you cannot choose these types of fields for creation.
Possible work around would be to create Additional Text Area Fields allowing for greater amount of data to be stored in Activities at one time.
Salesforce doesn't allow Long text area and Rich text area fields on Event object.
So, you can create a separate object like ActivitySupport and create a Rich text area field in that object. Also, you need to create a EventId (text 20) field for a reference.
Create a visualforce page with
standardController = Event with a controller extension.
Add that visualforce page in the Event page layout.
So, during event creation, this field will not get displayed as per standard create page functionality of Salesforce, But after event is created, you can edit this field which will be available at layout and save data in the separate AcivtitySupport object which is linked to EventId.
To display exiting records which contains Rich Text area values, you need to fetch that upon passing the EventId.
You can try this approach. If you stuck then I will help you providing the code.