Hello Lisa,
Welcome to the Community. I can clarify things about mailing a check payment to a vendor using QuickBooks Bill Pay.
For Check bill payments, the estimated processing times for the delivery is 10-12 business days. They'll also receive an email twice.
The first email will notify the vendor that you scheduled a bill payment to them. The second email is a notification that the payment is on its way and when to expect the bill payment.
Also, did you know you can make a stop check request in QuickBooks Bill Pay? I have a link here you can use as a reference on the process: Learn about QuickBooks Bill Pay.
We're always available if you have additional questions about paying contractors in QuickBooks. Click the Reply button, and we'll be sure to get back. Take care.