They are all correct. - 请向你家属问好。 - 请向你家里人问好。 - 请向你全家问好。 family: 家属 家里人 全家 -> all of your family members You can also say "家人” here. I would say 家属 is the most formal of all, next is 家人， then 全家 , then 家里人。 全家，家人 ，家里人 are all very commonly used in spoken Chinese. 家属 as family is usually used in written Chinese and randomly in spoken Chinese. But it could also refer to your spouse/partner/date when in Spoken Chinese, especially in a causal talk among young people. 请向 can also be replaced by "请帮我向“， ”请代我向“ 请帮我向你家人问好。 请代我向你家人问好。 Hope this helps.

you can't say “家属”, you should “代我向你的家人问好”

代我向家人问好

formal： 请向你的家人转达我的问候。 informal：替我问好 or 代我问好 the word 替 or 代 is an abbreviation of 代替。

i think a more casual way should be '替我问好‘ (say hi for me). and if you want to add the objective, maybe '跟家里人问好’。