prefer to do or prefer doing?

You can use ‘prefer to (do)’ or ‘prefer –ing’ to say what you prefer in general:

•  I don’t like cities. I prefer to live in the country. or I prefer living in the country.

However there are differences in structure after prefer.

I prefer	something	TO something else.
I prefer	English	to German.
I prefer	doing something	TO doing something else.
I prefer	studying English	to studying German.
I prefer	to do something	RATHER THAN (do) something else
I prefer	to study English	rather than (study) German.