I was wondering, if the main account holder can read or get any info from another phone on the shared plan?
The account owner can see the call logs (numbers dialed and when), text message log (numbers and when the messages are sent or received) and the data amount including when the system records the usage. The account owner doesn't have access to the contents of the text messages.
Is there anyway to block that from happening?
No. You could set up your own account or get a prepaid phone if you'd rather not be part of a shared account.
Since the account owner is (financially) liable for all the activity on the account, the account owner should be able to see what's happening. Having your activity viewable by the account owner is a tradeoff for a lower bill because you are sharing the account.
As tikibar1 said, the way to prevent that info from being viewable is to set up your own account.
Does that mean they can read my emails as well? I'm just comparing what
would be better staying on someone's shares account or just getting my own
The only way they could read the email is by looking at your phone, or having your email password. Email would show as data usage, but the individual emails are not visible.
What the account owner sees is a list of all calls made and received, numbers involved, dates, and times. Texts show up on a list of numbers texted to and received from, dates and times, but not the content. Email, apps, browsing, etc show up as data usage, but no specific info is shown.
Hope that helps.
