Will family member see my content if we share iCloud plan?

I have 4 iPhones and we each pay 0.99 a month for upgrade 50GB iCloud storage

I noticed that the 200 GB only costs 2.99. The question is, will my family member see on content on all the phones if we upgrade to 200GB shared family storage? We want to be economical but also want to respect all of our privacy.

thanks