Is it possible to send an electronic payment in USD to an international vendor

You can signup for a Melio account for free to integrate with QBO and pay your vendors internationally. The fee is $20 per transaction.

https://affiliates.meliopayments.com/pricing

You can get $100 as cashback to pay the first bill.

https://affiliates.meliopayments.com/cashback

You'll be please to know that you can send payment to your international vendor, @andiecava.

As mentioned by @4Gal, you can sign up for a third-party app like Melio. This allows you to send international payments. 

You can also sign up for QuickBooks Bill Pay. If you plan to sign up to this service, you'll need to turn on the multicurrency before sending international payments. This step is necessary to prevent sync errors when adding a vendor, bill, or payment.

In addition, enabling this feature will result in a permanent integration of currency conversion information into the system. A gentle reminder that once this feature is activated, there will be no option to turn it off. If you need help deciding whether to proceed, we recommend seeking advice from an accountant.

If you still wish to turn it on, here's how: 

1. Go to the Gear icon, then select Account and settings.
2. Click the Advanced tab 
3. Scroll down and select the Edit or Pencil icon beside the Currency section.
4. Tick the Multicurrency and read the important message.
5. Tick  I understand I can't undo Multicurrency, then hit Save
6. Once done, click Done.

Here's a screenshot for guidance:

For detailed information, refer to this article: Set up and use multicurrency.

To learn more about how the payment process works using the bill pay feature, check out article: Learn about QuickBooks Bill Pay.

I'm still all ears if you need assistance signing up and sending your payments to an international vendor. Just tap the reply button below. 

This used to work directly with QBO.  Now it is separate, but there has been no real explanation.  I am extremely disappointed that there was no admission that this has changed and no clear fix to the issue.  It looks like Melio works fine, but is an extra step that must be done in QBO.  Along with all the other annoying extra steps

It's disappointing you have to turn on multi-currency vendors to send an international payment in USD. I may stick to Melio since I can't undo multicurrency once I turn it on and don't know what else it may affect.