Please see answer on this link central.xero.com/s/article/Add-adjust-or-remove-payment-terms-or-advice-on-invoices-UK#:~:text=Click%20Save.-,Click%20the%20organisation%20name%2C%20select%20Settings%2C%20then%20click%20Invoice%20settings,static%20text%20on%20your%20template.