What's the easiest way to deposit a cash payment into my QuickBooks checking account?

You can use the Transfer feature to move this cash payment into your QuickBooks Checking account, @Kasey M.

Before that, make sure to connect an external bank account to get this cash transferred successfully. Then, you can follow the steps outlined below to achieve the task:

1. Go to Banking services, then select QuickBooks Checking.
2. Pick Transfer and then choose the option to transfer money between your accounts.
3. Enter the cash amount.
4. In the From field, select (+) and choose your connected bank account.
5. Select your QuickBooks Checking account in the To field.
6. Enter the amount you want to transmit.
7. Hit Finalize transfer.

Check out this guide for complete instructions: Use your QuickBooks Checking account.

Moreover, you can read these resources to get more insights about using QuickBooks Checking and how to handle uncategorized transactions once downloaded:

• Learn more about QuickBooks Checking
• Manage your QuickBooks Checking transactions

Please let me know if you need further assistance with managing your finances. I'm always available to help and ensure that everything is accomplished.

@Kasey M 

After you've recorded a payment against an invoice, then when you start to create a deposit you should be prompted to include it, and any other payments, in the deposit. You can then select which ones (if multiple payments are available) to include in the deposit.