Hi,
1. It is possible in BPF once I submit the Plan to approver, and the approver recieve an email with notification and when the plan is rejected by the approver its send a notification to that specific owner?
Yes, this is standard functionality of BPC.
2. For implement the Point number 1, the workstatus using the workstatus is mandatory?
Workstatus is entirely different, as standard function nothing to do with BPF. If you want to lock the data,
You have to perform manually.
There is way to automate this work status change with BPF steps but it's custom ABAP development.
Shri