Thanks for keeping us posted, iasbalaskas-gmai.
You can not change the currency within an invoice. When you create the customer you state how they will be paying you. If you have set up a customer John Smith to pay in GBP for example but they will also be paying sometimes in USD you would need to set up a second customer who pays in USD. That customer will need to be named slightly different for example John Smith USD.
The Multicurrency feature is available in QuickBooks Online Essentials and Plus versions. You can check your current subscription and if your version doesn't support the feature you might want to consider upgrading. You can click here for more details.
However, if you have QuickBooks Essentials and Plus and you're still unable to turn on Multicurrency, we can perform a few browser troubleshooting steps. Log in to Quickbooks Online using a private browser. Then, you can follow the steps below to enable the feature:
- From the gear icon, select Accounts and settings.
- Select Advanced from the left menu and click on the Currency section.
- Choose your Home Currency and toggle to turn on Multicurrency.
- Read the conditions and check the I understand I can’t undo Multicurrency box.
- Click Save and then Done.
If you're able to do the process, you can switch back to the main browser and clear the cache. Other support browsers can also help you get rid of these kinds of issues.
Visit this page for more details on how Multicurrency works.
I'm just here if you have other questions. You take care always and have a great day!
