This topic mentions default invoice languages per client:
However, most of my clients are from areas other than English language/GBP.
It would be nice to be able to set a language other than English and currency other than GBP as a system default — rather than having to remember to set them on per-client or per-invoice basis.
If you haven’t already, please feel free to add your vote to the other thread for the language.
However, with the default currency, you may be able to change this with a bit of JavaScript if you have a Power User Subscription. I’ll have a look and come back to you shortly.
[Edit]
Adding this code to your custom scripts (Account Settings >> Design Customisation >> Advanced HTML/CSS Customisation) will change it when creating a new client:
As QuickFile is designed for UK based businesses, the base currency (and therefore reporting) is fixed to GBP unfortunately.
You can however, change the language and currency for individual invoices. The below guide will hopefully help set up the multi-currency support, if you’re interested: