I am trying to add the bank details to sales invoices and have tried all the suggested fixes to no avail. I have repeatedly tried Custom Fields but it looks very untidy.
The guide mentions Footers in Settings, but there is no such item in settings.
And yes, as @ries mentioned, don’t forget to keep your manager updated. The Footers feature is only there in version 22.8.10. Your 22.7.19 version will not have the Footers feature.