I added a new vendor but when I go to link them to a transaction, they do not show up.

It can be challenging when you can't link your vendor to transactions, korey. I'm here to ensure this gets taken care of.

As of now, we have an ongoing investigation related to being unable to link the newly created vendor not showing up as an option in the register. Our engineers are actively working to ensure this gets resolved as soon as possible. 

I recommend contacting our QuickBooks Online Support Team. Doing so ensures you'll be added as one of the affected users. That way, you'll receive updates about the status of the investigation.

Here's how:

1. Go to the Help (?) icon at the top.
2. On the Assistant tab, click Talk to a human.
3. Enter your concern in the Type something field, then click the Send icon.
4. Click on I still need a human.
5. Select Get help from a human.
6. You can either select Chat with us or Have us call you.

To ensure you receive timely assistance, please check our support hours.

Moreover, I've added this article to help you review downloaded bank and credit card transactions to ensure your books are accurate: Categorize Online Transactions in QuickBooks Online.

We appreciate your patience on this matter. Please keep us posted if you need assistance managing your expense transactions or bank data. We're always here to help you out.