To create Case records for Salesforce WhatsApp Messaging Sessions, we can make use of Record Triggered Flow on Agent Work entity.

Sample Flow:

Flow Start Element:

Fetch Messaging Session Get Records Flow Element:

Case Check Decision Flow Element:

Conditions:

Messaging Session from Fetch_Messaging_Session > Case Id Is Null True.

Messaging Session from Fetch_Messaging_Session > Channel Type Equals WhatsApp

Create Case Create Case Flow Element:

Assign Case Id to Messaging Session Assignment Flow Element:

Update Messaging Session Update Records Flow Element:

Output: