Two-factor authentication for Apple ID

Apple IDs are personal; they shouldn’t be shared any more than you would share a toothbrush. If you share an Apple ID with someone else many bad things will happen. Each user should have their own Apple ID, then you can create Family Sharing→What is Family Sharing? - Apple Support. That way you can share what you want to share and not share what you don’t want to share.

It is OK to share an Apple ID among devices used by one person, such as an iPhone, an iPad and a Mac; in fact, it is a very useful thing to do. But not between devices used by different people.

Here is Apple’s FAQ: https://appleid.apple.com/faq/#!&page=faq. See the 4th bullet item.

And here is Apple's expansion of what I've posted→Make sure that each family member has a unique Apple ID - Apple Support

Sounds like everybody is using the same AppleID.

Each user should have his/her own AppleID.

The issue you’re experiencing is just the “tip” of a very nasty “iceberg” of problems.

Security and your Apple ID - Apple Support

Set up Family Sharing - Apple Support

Create an Apple ID for your child - Apple Support

Use parental controls on your child's iPhone, iPad, and iPod touch - Apple Support