When I try to download games or apps, it don't ask me anymore for my password/permission to download?

my account is connected to several devices (my husband and my kids). I was happy about so that I don't have to worry when my kids try to download games with fees But now that permission before they can download is no longer there? I don't know what happen..... I'm afraid of this..

BEfore someone download something there's always something popped out that I have to put my apple password So that they can download.

anyone can help me?

thanks