Use "would prefer" to say what someone wants (to do) in a particular situation, about a specific preference
You can say would prefer to (do) or would prefer (do)ing. Would prefer can be abbreviated to  'd prefer.
-Would you prefer tea or coffee?
Coffee, please.

- Would you prefer go by train?
Well, I'd prefer to go by car.  or
Well, I'd prefer going by car

Use "would prefer" when making a comparison "I Would prefer.... than"
Would you prefer go out this evening?
I'm tired, I'd prefer to stay at home than go out.