How do I enter a payment to a vendor when there is no invoice in the system?

Click +NEW

Under VENDOR click EXPENSE

Pick you Vendor in the dropdown 

Enter all info needed

Save

Thanks for the response. However, there will be no bill coming from this vendor. How can that be handled? I know with customers if they pay in advance the system saves it as a deposit for allocation when we invoice them. 

The steps provided by @Just_me is correct, @accountingnwt. Let me add further details and guide you through handling this vendor payment accordingly in your QuickBooks Online.

You can record your wire transfer as an expense since you will pay your customer. To do so, you can refer to the steps provided below:

1. On your left menu panel, select the + New button.
2. Under vendors, click Expense.
3. Choose the vendor that you want to pay in the Payee field.
4. In the Payment account field, click the bank account you want to have the wire transfer.
5. In the Payment Date field, enter the date of purchase.
6. Select the Payment Method from the dropdown list.
7. Input Wire Trans or WT in the Ref no. field.
8. Specify the expense Account that tracks the charges.
9. Enter the Amount of the purchase, then hit Save and close.

Additionally, you can visit this article for a detailed guide on recording wire transfers: Record a wire transfer in QuickBooks Online.

Moreover, in case you want to manage your expenses in QBO, you can refer to this article: Enter and manage expenses in QuickBooks Online.

Please don't hesitate to comment below if you have other payment concerns and questions about managing your QuickBooks Online account. I'll be willing to help at any time. Stay safe.

@accountingnwt 

The proper entry depends on the purpose of the payment.  Why did you pay them and why will there be no future bill?  

I have no idea why we did that.

@accountingnwt 

Then presumably you have a credit with the vendor, yes?  If so, assign A/P to the payment.  That will allow you to apply it to a future bill.  

I was told there would be no future bill.

@accountingnwt 

You need to know the reason for the payment or there's no way to properly record it.  Ask the vendor if the payment covered a balance due.  If so, have the vendor send you the bill and enter the bill and use the wired payment to pay it.  If there was no balance due, then you must have a credit with the vendor.  Assign A/P to the wired payment and apply it to a future bill.  Those are your options.