Hello there, rachelle14. I understand you want to save the email address without resending the invoices.

If you're referring to your customer's email address, here's how you can save it:

1. Hover to the Sales menu, then select Customers.
2. Locate the customer you want to update and double-click it. 
3. Click Edit and type in the email address in the Email section. 
4. Once done, hit Save. 

Meanwhile, if you're referring to your company's email address, here's how to save it:

1. Hover to the Gear icon, then select Account and settings.
2. Choose Company, then click the Company info edit icon. 
3. Update your Company email; this is where QuickBooks can contact you, while the Customer-facing email is where your customers can contact you. It will show in your invoices and other sales forms.
4. Once done, click Save.

Moreover, if you've received a payment from your customer, it's important to record it in QuickBooks to ensure that the invoices are marked as paid. This way, you can keep track of your business's financial transactions and maintain accurate records. 

On the other hand, you can customize your invoices, estimates, and sales receipts in QuickBooks Online. Customizing the appearance and layout of your sales forms is an easy but effective way to enhance your business communications. 

I'm still around if you need further assistance managing email addresses and invoices in QuickBooks Online. Kindly click the reply button below to enter your queries.