Congratulations on your wedding

Answer 1

恭喜你们结婚 [gōng xǐ nǐ mén jié hūn]

There are many classic Chinese phrases or idioms for use in weddings, typically a few are used together in 1 statement.

example:

祝福你们新婚愉快，幸福美满，激情永在，白头偕老！

zhu(4 fu(3)) ni(3) men(2) xin(1) hun(1) yu(2) kuai(4), xing(4) fu(2) mei(3) man(3), ji(1) qing(2) yong(3) zai(4), bai(2) tou(2) xie(2) lao(3)!

rough translation:

'Wishing you newly-weds a joyous wedding, happy marriage, everlasting passion, together ever after to a ripe old age!'

For the simplified version, one can just use 祝福你们新婚愉快! ('Wishing you newly-weds a joyous wedding!)