I'm here to share further details about classifying your petty cash transactions in QuickBooks Online (QBO), @Ashleynd. This way, you can keep your account updated and manage your sales accordingly.

After creating a new petty cash account as directed by my colleague above, you can enter a sales receipt for the sales received and expense transaction for the expenses made using the petty cash. Then, whenever you take money from the petty cash account and deposit it to the business bank, you'll have to record a transfer in QBO. Here's how:

1. Go to the + New button.
2. Select Transfer.
3. In  the Transfer Funds From field, select the petty cash account.
4. From the Transfer Funds To drop-down list, select the bank account that the money is going to.
5. In the Transfer Amount field, enter the amount being transferred.
6. Edit the Date field.
7. Enter a description of the transfer in the Memo field (optional).
8. Select Save and close or Save and new to complete the transfer.

I've attached a screenshot below that shows the last six steps.

To further guide you in putting cash in and out of your petty cash account, I'd recommend checking out this article: Manage petty cash in QuickBooks Online.

Also, I'd recommend reconciling your accounts every month. This is to monitor your business' income and expenses and determine any possible errors accordingly. You can refer to this article for the step-by-step guide: Reconcile an account in QuickBooks Online.

Let me know in the comments below if you have other concerns about your petty cash account and managing its transactions in QBO. I'm just around to help. Take care always.