Question

¿Estan bien escritas?

what are you going to buy your parents for their anniversary?
what are you going to get your friends for their birthdays?

Answer 1

corrección:
what are you going to buy TO your parents for they anniversary?
what are you going to get TO your friends birthdays?

Answer 2

What will you buy your parents forma their anniversary?
What will you get tour friends fir their birthdays?