No. The custodial parent or state child support agency would need to file suit, obtain a judgment and then use the judgment to levy the obligated parent's bank account, or the account holder would need to voluntarily allow withdrawal of funds. A judgment is not necessary for an obligated parent's tax refund (state or federal) to be seized for back child support.
no
no it can't cause that is you account not somebody else
They could but it is illegal without your permission.
No one can write a check on any checking account that does not have them as a signer. If their name is not on the account it is called fraud. If their name is on the account a check can be written without permission, even if you are the main signer
Yes they can. They can also suspend your driver's license without notification. They can attach to any assets that you may have to obtain the back child support including checking, savings, a home, a car that you own etc.
Legally, in most cases, yes. Ethically, no, not without permission.
Yes
No. It is your account and the bank cannot move funds from one account to another without your approval or rather without you asking them for it.
No its 18
Change your passwords.
Of course. That's the purpose of a "joint" account.
No. A bank cannot do that. A bank cannot transfer money from one account to another without prior approval or permission from the account holder from whose account money is going to be taken. If such a thing happens, the affected customer can sue the bank.