Bank accounts can have one or more account holders: this ownership is considered joint and several or indistinct if any one of the holders can make use of the money on their own behalf, without the authorisation of the other holders. Instead, it will be joint or joint and several if it requires authorisation. And it will be subordinate if each holder has a different status. For example, whoever is in first position will not need anyone else's authorisation to carry out operations, but the person in second position will need it from the person in first position, and so on.
It is a different matter if the holder is the authorised signatory of the bank account, in which case the signatory will have appointed them to make use of the money on their behalf, but they will not be the owner of the account, nor of its funds. The authorised person will have a signature to manage the account on behalf who they represent, and will be able to make use of the balance, write cheques and make transfers, and even request bank information without the permission of the account holder. However, not being the holder will not have any tax implications, nor will the person in question be able to apply for credit or debit cards in their name or cancel any of the represented individual's banking products; not even block or modify an account or product in the event of their death.
Appointing an authorised party
To authorise a person to carry out any authorised activity on your account, you simply have to request it in writing at your bank branch, providing a photocopy of your ID card.
Ownership and authorisation for an open account
Normally, account holders cannot be added after the account has been opened, but authorised persons and proxies may be added.
What if an account holder dies?
When this happens, their heirs will take on their rights and obligations, but in any case you will have to inform the bank, submitting the death certificate. At that point, the balance of the account will be frozen until the inheritance is settled. If the account ownership is indistinct, the other owners may continue to manage it. And if you have joint ownership and one holder dies, the others will have to have the consent of the heirs.