how to create an entity like activities which contain different types of record(task,phone call, appointement..)

hello,

how to create an entity like activities which contain different types of record(task,phone call, appointement..)?

I have created a few entities(request of implementation of software, request of reimbursement and payment..) and process, I want to create an new entity in order to collect different types of requests.

Thanks,

Siyu