DDD - Should entities create entities?

Question

In my domain I might have a entity called User that represents a person and Tenant, an entity that represents a business.

One might think that this is a administrative user, and as such, it should be able to register new users, which in terms of code would be translated to basically 3 forms:
-adminUserInstance.CreateUser(newUserDTO);
-tenantInstance.CreateUser(newUserDTO)
-newUserInstace.SelfSave()

Being newUserInstace.SelfSave() a necessity because of self-registration, does the other two make sense? Should i keep only the self registration and turn to a model of affiliation, where the same user can be part of multiple tenants?

In broader terms: should Questions/Answers be created by Users or self created and then tied to a given User? and on even broader terms: Should entities hold the knowledge to create other (not any-others) entities or the entities should be able to create themselves and have the "requester", for example, call a domain service that will bundle them up?

Answer 1

In broader terms: should Questions/Answers be created by Users or self created and then tied to a given User? and on even broader terms: Should entities hold the knowledge to create other (not any-others) entities or the entities should be able to create themselves and have the "requester", for example, call a domain service that will bundle them up?

Udi Dahan's technical guidance was that you should always get an entity, and use it to create the new entity. "Customers don’t just appear out of thin air."

That said, creating aggregate root entities is weird; not "wrong", but it deviates from the usual patterns of dispatching commands to the aggregate you are going to modify.