It's great to assist you here in the Community space about handling your invoices, @Fi_1993.
In QuickBooks Online (QBO), we can manually add the payment instructions in the customer message or the Footer text in your custom invoice template.
However, since you're invoicing in different currencies, you'll have to manually change the payment instructions, including the details of the bank every time you invoice in a foreign currency. Once you make a change to your custom template, it'll apply to all of your existing templates.
On the other hand, if you're using QBO Advanced, we can automate this process using custom fields. You can create a custom field in the customer profile and invoice named Payment Instruction and ensure to turn on the Print on form option.
Moreover, in the customer profile, you can enter the specific payment instructions specifically for that customer in foreign currency. Once you invoice your customer, the payment instructions will automatically show on the invoice.
To know more about personalizing invoices, I've added this article which includes editing custom templates: Customize invoices, estimates, and sales receipts in QuickBooks Online.
In case you need to void or refund payments you process through QBO, you can visit this link for guidance: Void or refund customer payments in QuickBooks Online.
Keep in touch if you have follow-up questions about handling your invoices in QuickBooks. I'll be around to assist you always.
