Canceling Flight Plan
Here in the US, we can have the following situations :
1. On an IFR flight plan, when you land, the tower closes the flight plan once you have landed, assuming you are going into a towered airport.
2. If you are landing at a untowered airport, (which may have an ILS, VOR etc approach), approach control will say bye bye and let you go to local advisory frequency at a safe distance from the airport, and you are on your own.
In this case ...
a) You can stay IFR and call from the ground once you have landed to close your flight plan. Approach usually remind you to call prior to switching you ... your cue to do ...
b) You can cancel IFR (closing your flight plan) whilst still talking to approach, in which case you are probably in non-Bravo/Charlie airspace. You are then under VFR rules. (This is my normal strategy)
There are some wrinkles to this, and the system is quite flexible, though I heard a big fight when a pilot cancelled IFR going into Houston Intercontinental, to doge getting queued up with other IFR arrivals. That might be a whole other discussion.