What is the address for the bank to mail a check for quickbooks cash deposit. I want to deposit more than $50,000 in one go

I would take that to the bank personally.  I don't use QB "online", but don't see why you couldn't do that?

I can share some information about transferring funds from your bank to QuickBooks cash, @pinto1. 

To check if there's a way to send a check to your QuickBooks cash account, I suggest reaching out to our Customer Support to verify. They can provide you with the right information in a safe and secure environment. You can reach them by going to the Help icon at the top right of the account. Follow the steps below: 

1. Go to the Help icon to connect to a live support agent. 
2. Click on the Contact Us button and provide some details about this concern.
3. Provide us some information about your concern in the What can we help you with? box and click on Continue.
4. You'll now be provided options on how to connect to our Customer Support.

You can check this article for more information about the different types of support we offer and their availability: QuickBooks Online with Payments & Merchant Service Center Support. 

Here's everything that you need to know about the Cash Flow planner, QuickBooks Cash account, QuickBooks Debit Card, and Envelopes: Learn more about QuickBooks Cash accounts and the Cash Flow menu.

I'm always here if you still have questions about your QuickBooks cash account and or anything else, by leaving a reply below. Take care and have a wonderful day!