Your question is very broad and thus varies by platform.

Most new Cats have ingress queuing and egress queueing. For lower end switches this can normally be found in the data sheet for each device. For chassis switches it is usually dependant on the line card - again, check the data sheet for the line card. 'Sh int cap' may tell you depending on the platform

Ingress queueing is generally storing packets as they are received before they are switched and egress queueing stores the packets before they are serialised (put on the wire). Ingress queues are generally quite small as your ingress throughput would have to max the fabric/backplane throughput in order to experience congestion, which is generally rare. Egress queues are generally larger as egress throughput may be less than the aggregate being pushed out the interface.

HTH,

Paul