I need to make a payment to the UK National Insurance. They want me to include an 18 digit reference number with the payment. If I write this in the reference number field when I make a bank transfer to them, will they be able to see it when they receive the transfer?
they will see what you write as reference number. yes.
good than is not necesarry in normal payments
Be careful with scheduled transfers. The app (Android 5.49) loses the reference field when you enter the transfer and use “plan transfer”. But you can select the transfer in the list of planned transfers and add a reference afterwards.