When I send my invoice it shows a balance forward amount when their is none

Not usre if it will be helpful, but I found this link to another thread, with the same issue. 

https://quickbooks.intuit.com/learn-support/en-us/reports-and-accounting/an-invoice-shows-a-balance-...

Good Luck. 

Hello there, @chernandez1.

Let me share with you an idea about the balance forward in your customer's invoice.

It might be your customer has open invoices that's why the balance forward is showing. You can run the Account Receivable Aging report to check the open invoices for your customer.

Here's how:

1. Go to the Reports tab.
2. Search Accounts Receivable Aging Detail.
3. Click the Customize button to pull up the specific customer you're looking for.
4. Choose the Filter drop-down arrow.
5. Put a checkmark on the Customer box.
6. Look for the customer by clicking the drop-down arrow in the Customer field.
7. Hit Run Report.

Review the report and if the invoices are already paid, look for the payments, and record them.
 
You might want to use these articles in case you need help customizing and memorizing the report:

• How to Customize Reports
• Memorize reports in QuickBooks Online

If you have additional questions, feel free to leave a message below. I'll be around here in the Community to help. Keep safe, and have a great day.

Chiming in late so you may have already found a solution but if not...here's an idea.  I find that my customer balance is inflated on the email message I send out (for a new invoice).  The reason for this in my experience is that a payment (for an old invoice) was received and dated after the new invoice date.  The email going out with the new invoice seems to take a balance snapshot in time as per the date of the new invoice...not as per the date of the email.  Hope that helps.