Thanks for checking in with us. Let me provide some information about the Multicurrency feature, Annie159.

I appreciate you for opening a new QuickBooks Online (QBO) account. When turning on the Multicurrency feature, your current currency becomes your home currency. This is based on the currency of the country your business is physically located.

Then, the default value for all customers, suppliers, and accounts ( income and expense ) is your company's home currency.

For the exchange rate (EUR - USD) that you'll need to use, I'd suggest consulting your accountant about this one. They'll provide you detailed information on what's the exchange rate you need to apply in the beginning balance. 

If your customer uses a currency that's different from yours, just assign a foreign currency to them. For the steps and details, check out this article: Assign a foreign currency to a customer in QuickBooks Online.

To learn more about Multicurrency, see the Multi-currency FAQ article. From there, you'll get answers to frequently asked questions about using this feature. 

Visit our QBO Help Articles page for more insights about managing your business in your account.

That should do it. I'm just one click away if you need a hand to run your financial reports or any QBO related. I'm always here to ensure your success. You have a good one.