Hello there, Rlambert0412.

I'm here to give answers to your email inquiry when entering it in Bill Pay and why it changes the email in your vendor account in QuickBooks online. 

When you process a vendor payment via Bill Pay, they're the ones responsible for sending the payment information to the email address on file for the vendor in the Email Address field. That said, if you want to change your vendor's email address, you'll have to change the vendor's email from there.

Here's how:

1. Go to Vendors in the navigation menu, then click Edit.
2. Enter or change the Vendor's email address.
3. Once done, click Save.

You can read this article to learn more about using QuickBooks Bill Pay for QuickBooks Online: Learn about QuickBooks Bill Pay.

Moreover, if you want to review which bill pay add-on you have in QuickBooks Online, you can visit this article to learn how: Check which Bill Pay you are using in QuickBooks Online.

If you have other questions about configuring the emails in Bill Pay, don't hesitate to click on the Reply button and leave a comment. The Community will always be here to answer them. Have a good one!