Elderly relative created joint bank accts. Balance at death greater than 14K. Are gift tax & estate tax returns necessary? Does the estate need to pay gift tax?

Joint bank accounts were created in order for the daughter to pay bills. Daughter did not contribute anything to the accounts.  Daughter received sole ownership of the accounts at the death of her dad. The balances are significant.  Does the daughter have to pay taxes on the account balances or does it come out of the estate?  Does she or the estate have to pay gift taxes, or would it be applied to a lifetime exemption?  THanks for any guidance you can provide.