What I understood by the documentation is that:
kubectl create can work with one object configuration file at a time. This is also known as imperative management
kubectl create -f filename|url
kubectl apply works with directories and its sub directories containing object configuration yaml files. This is also known as declarative management. Multiple object configuration files from directories can be picked up. kubectl apply -f directory/
Details :
https://kubernetes.io/docs/tasks/manage-kubernetes-objects/declarative-config/
https://kubernetes.io/docs/tasks/manage-kubernetes-objects/imperative-config/