Do I need to mark down cash payments and bank transfers separately?How can I downloaded previous invoices that are already paid?

Hello there, theshabbiedog-ho.
 

Once a bank account connects to the online banking feature, QuickBooks will automatically download your transactions. The data is not entered directly into your account. You'll have to manually create an invoice and receive payment or use banking to categorize the transactions.

First, create an invoice. Here's how:

1. Go to the +New button.
2. Under Customer, select Invoice.
3. In the Amount column, enter the correct amount.
4. Then, Save and Close.

Then, apply the credit to the invoice that you've created:

1. Go to the + New button and choose Receive payment.
2. Select the customer, then the credit and the invoice.
3. Click Save and New once done. 

After that, categorized banking transactions, here's how: 

1. Go to Bookkeeping and then, select Transactions, 
2. Select the blue tile for the account you want to review.
3. Go to the For Review tab.
4. In the For Review tab, you can add, match, and categorize transactions.
5. Select the Add or Match button to complete the process

To learn more about managing downloaded transactions, feel free to read the details from this link: Categorize and match online bank transactions in QuickBooks Online.

You can also use bank rules to allow the system to categorize transactions from your bank automatically. You can use this link as your reference: Setup bank rules to categorize online banking transactions in QuickBooks Online.

Feel free to get back to us if you need additional assistance. Have a great day!