It’s an uber-useful and free invocing system. Just type in your info, upload your load, add a message and their email address and send. That’s it. A really quick and useful way to invoice your clients for free.
I would refrain, however, from adding confidential and private information from this system, such as bank account details. Instead contact your clients directly.
If you want something more secure, then this is pretty much a stripped down version of the invoicing tool built within FreeAgent. You can get the full version with a FreeAgent subscription which for soletraders starts at £19+VAT per month and £29+VAT per month for Limited Companies. You can save 10% off every month with a FreeAgent Discount Code.