if a joint account is made by the bank between an elderly lady of 89 and her daughter with the elderly ladys own savings account. can the mandate form be sent to her daughter to get signed by both partys involved or should the mandate form be signed in front of a witness from the bank when it concerns a large sum of money.
With my bank, if the joint account allows transactions from either person, then one person can confirm the transaction based on the fact that when the account was originally set up, it allowed such transactions. It may not necessarily need both signatures. You will normally need to confirm the ID of the person signing - sometimes, you may need extra ID for a large amount.
As soon as that money is in a joint account then legally it's as much one person's money as the other's.
Some joint accounts are set up as "either signature" and others, less commonly, as "both signatures" to carry out transactions. (If either of you/them have a bank card with the account then, by definition, it's "either sigs" so the daughter can withdraw the balance in full without the consent of the elderly lady).
In neither case (either/both signatures) would someone be required to witness the signature on any form.
If it's more convenient for you/them then the bank should be happy to post the form to you anyway.