Clone button unavailable when you view Activities in Salesforce Classic

Why the Clone Button Is Unavailable in Salesforce Classic

Salesforce Classic does not support the Clone button for Activity records (Tasks and Events). Adding the Clone button to a Task or Event page layout does not cause it to appear when viewing Activity records in Salesforce Classic. This is a known platform limitation.

Alternative in Salesforce Classic: Use the Save & New Button

In Salesforce Classic, use the Save & New button, which provides the same function as the Clone button for Activities. When you click Save & New, a new Activity record is created with the following standard field values pre-populated from the previous record:

• Assigned To
• Subject
• Related To
• Name

Lightning Experience Alternatives

The Clone button for Events is not currently available in Lightning Experience. The Save & New button is available in Lightning Experience; however, it only carries over the Subject field value — it does not replicate all fields as it does in Salesforce Classic.
As an alternative in Lightning Experience, use the Create Follow-Up Task Lightning action. This action copies the following information from the original Task and provides functionality similar to the Save & New button in Salesforce Classic:

• Assigned To
• Subject
• Related To
• Name