Shared apple account
I have 3 phones on my account. Texts and emails going to ALL 3 accounts. How to stop!
Question marked as
If the 3 phones are not being used by the same person they should not be sharing an account. 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
