STAR - Standard Terminal Arrival Route. Yes, you're quite right. I was typing on autopilot this morning!
As an airline pilot, it's unlikely you will ever be required to write a flight plan as your ops/flight planning department will look after all that for you. However, if you ever do have to write one, you would normally file for the SID/STAR that best suits your route of flight. ATC can then either clear you as filed, or substitute an alternative SID or STAR that better suits their tactical picture. As I've already said, the clearance and what you actually fly may be very different...
You can indeed file direct to your destination airfield without including a STAR, but you would expect to be assigned one before entering the terminal area - so you need to have the STAR information with you!
Scroggs